The logic is indeed so; being late on the battlefield could endanger your comrades in less than a minute...
Consider the Battle of Kannabi Bridge: if the Yellow Flash had not been late back then, had demolished the bridge faster, and promptly supported Kakashi and Obito, rescuing Nohara Rin from being forcefully taken by a large rock using the Secret Technique: Camouflage Invisibility Technique.
Breaking the secret hand of Black Zetsu and Uchiha Madara behind the scenes, perhaps... Obito wouldn't have gone to the dark side.
Unfortunately, there are no ifs in this world. To save his mother, Black Zetsu would have targeted another Uchiha even if he didn't focus on Obito, such as... Shisui or his own brother Itachi.
Roy's mind raced, his gaze passed over Minato Namikaze to glance at Obito and Nohara Rin standing behind him.
Young and inexperienced, as he looked over, their expressions differed. The latter was curious... the former tensed, subtly moving closer to Rin as if declaring to Roy—
She's mine, don't even think about it!
Luckily, Roy's gaze came quickly and left just as fast, turning around to cast a look at Kakashi, the genius ninja known for breaking the record for the fastest graduation from the ninja academy. Half-covered face, he too was watching Roy with a hint of exploration, recalling the respect his father once had for the boy in front of him…
"Alright." Wrong is wrong, and punishment should be taken.
Roy spoke concisely, avoiding neither confrontation nor escape, with both hands in his pockets, waiting calmly for Minato Namikaze to continue.
The young man with yellow hair swaying, soon to gain great fame on the battlefield as the Yellow Flash, squinted and smiled…
"Simple," Minato raised a finger, "weighted running... Kakashi, Obito, Rin, the three of you along with Jin, carry a log each, circle the forest ten times, and time it for an hour, go!"
Kakashi and Rin were stunned, instinctively looking toward Obito... One person being late caused the whole team to be punished... according to Obito's personality, he would definitely ask the teacher angrily... "Why"... right?
But,
Today's Obito was extraordinarily strange,
Apart from feeling a faint vigilance due to Roy's casual glance at Rin, the usually loud-mouthed Obito peculiarly didn't retort but instead... silently took up a log on his own…
Kakashi and Rin exchanged a glance, both seeing a hint of surprise in the other's eyes!
Obito, disregarding this, didn't blame Roy at all, and with the log on his shoulder, he was the first to rush toward the depth of the forest, yelling as he went: "Move, why are you still standing there?"
Kakashi and Nohara Rin, logs in hand, followed,
Last was... Roy.
"Step... step…" Along with Obito, Kakashi, and Rin gradually moving away…
The boy said nothing, extended a hand towards a log standing in the empty corner, and with a pull of the hand... Magnetic Field: Suction... first time showcasing the Nen ability derived from legendary magician Moritoni... Iron-stained Bipolarity in Konoha…
A sudden suction brushed past Minato Namikaze's shoulder,
His eyes focused, watching the log uproot and break through the air towards the boy, pondering: "No-seal ninjutsu?"
In enormous surprise, confirming he hadn't seen Roy form any seals, his mind wavered, silent... watching the log land on Roy's shoulder, easily held in place, stepping away... Minato Namikaze returned to his senses for a moment, then kicked a log onto his shoulder as well, flashing to follow....
When students make mistakes, the teacher must also bear responsibility... This was what Jiraiya-sensei had taught him; said it was passed down from the Third Hokage... But,
Sarutobi Hiruzen acknowledged, he hadn't taught Jiraiya any knowledge about No-seal ninjutsu, or rather,
Even though he's renowned as a Ninjutsu Doctor across the major villages, there are hardly any No-seal ninjutsu he himself has mastered, otherwise, he wouldn't have failed to showcase them during the duel with his former disciple Orochimaru...
In the Hokage's office, a symbol of Konoha's supreme power,
The elderly man watched through the crystal ball as Roy, carrying the log, took the lead, slowly catching up to Rin, then Obito, finally brushing past Kakashi's shoulder to sprint ahead, trailing afterimages, "thud~" picking up and drawing deeply from the tobacco pipe slapped onto the desk, opened the drawer single-handedly, taking out the scroll with Roy's name, "Uchiha Jin"...
Spreading it open, pen in hand, pulling it to the end, and adding another line... "Demonstrated No-seal ninjutsu, self-created unknown, unknown origin, known... possessing suction function..."
Sarutobi Hiruzen's gaze flickered, pausing in thought for a moment, before adding another sentence at the end... "Whether all ninjutsu can skip the Seal stage... unknown..."
Finally, the old man laid down the pen, watching Roy sprint in front, as if strolling leisurely... with his lofty perspective, he could see farther, much more so than Minato Namikaze who had been immersed in Ninjutsu for over thirty years, hence, he was keenly aware of the preciousness of No-seal ninjutsu!
It's important to know, Seals were passed from Indra, originally a type of seal art he specifically created to help everyone in the Ninja Sect perform ninjutsu...
In essence, it is a process that cannot be omitted, as it guides chakra within the body along a fixed path through specific hand gestures, or stimulates the heart meridians, triggering an outburst of yang chakra to release Fire Style... or directs chakra to the kidneys, creating a liquid trait, releasing Water Style... or forces chakra at the meridian ends to vibrate at high frequency, releasing Lightning Style, among others... a necessary process!