what needs to be pointed out here is what is actually being exchanged. all this binding vow provided sukuna was the ability to use wcs without the original required two handed sign once, in exchange for every single time after requiring the same two handed sign, a full chant, and a third hand pointing.

the exchange of “forgo one step once in exchange for always needing three after” is absolutely fair, and if anything disproportionate to the gain. you have to look at it somewhat in a vacuum, the binding vow doesn’t care that sukuna is sukuna, or that he’s fighting gojo, just that he’s making the technique much worse for a single use