That wasn't a choice, it was forced. Congress forced the SLS to be an ultra expensive zombie of the Saturn V to let the people who worked on the Space Shuttle mantain their job. I don't think people understand how much of a ridiculous waste of money it is to use RS-25 engines on a rocket. Those engines are VERY expensive, but that's because they are meant to be reused.

Least they could have done is figure out a way to, at least, recover the first stage of the SLS.