@akbenothman
Josuke bubbles are half Kira's and half Josefumi's and have been seen to be having a "explosion" attribute still that Josuke can use
see the chapters where he fights the A. Phex Brothers where he pops one of the brother's cheeks off with his bubble or in the Vitamin C chapters where his bubble caused the frame of Damo's glasses to break or in the Urban Guerrilla arc where Josuke tried to shoot expanding/exploding bubbles at the pet rock animal and the moment where gasoline filed bubbles, with the help of a lighter cause a FUCKING C4 EXPLOSION
overall tho the bubbles can be utilzed in many ways other than stealing
so what Josuke possibly did would be the same effect as knocking someone out with a punch by popping the bubbles he could do enough pain to his head to cause the body to go to "defense mode" and make him faint, which could only possibly be useful against non-stand users.
bubbles that store the stolen thing still float around and return back to the person who he stole it from after they pop, so its not a case of stealing conciousness or anything of that sort since the bubbles are popped instantly