What Uchiha Yu used was not the Shadow Clone Technique, but the Uchiha clan's own Sharingan Ocular-Power Clone—a prototype Senju Tobirama had "referenced" when developing the Shadow Clone Technique.
After the Shadow Clone Technique was developed, this Uchiha technique, which required a Three-Tomoe Sharingan to perform, was surpassed in every respect: practicality, duration, functionality, flexibility, and more.
The gap was worlds apart, so this technique from the Warring States Era was naturally phased out. Even Uchiha ninjas no longer used it. Only because Uchiha Yu, as a chūnin, had not yet learned the Shadow Clone Technique did he have no choice but to use this obsolete technique.
The Uchiha clan naturally possessed the Shadow Clone Technique, but Uchiha Yu had never learned it. He could only blame himself for being too good at keeping a low profile. He had been an utterly invisible minor figure both in Konoha and within the clan, so naturally no resources had been directed his way.
Without a powerful clan elder in charge gifting it to him, he could only buy ninjutsu with money, as permitted by the clan. But he had been desperately poor before and simply could not afford an A-rank ninjutsu.
After finally swindling enough revival funds to become rich, he had been busy with his grand cultivation endeavor—working to adapt to the physical and mental changes of the Foundation Establishment stage, while battling the heart demon deep within his mind. He had no time to think about fighting ninjas at all.
And so, it had been delayed.
Fortunately, he had found a substitute ninjutsu in Uchiha Revival Capital. Otherwise, he would have had no way to deal with the Root ninjas who had tracked him down this time, and he would very likely have ended up on Shimura Danzō's blacklist.
Although