I’m kind of on the fence over this issue.
If you want to run a very large number of games on your device, and/or emulate other more powerful systems, and/or have a wider choice of controllers, then a Pi is clearly a better option. It’s hardly worth arguing about at this point.
However, some people around here have an irrational hatred of the Pi, and no argument you present will persuade them to buy one. There are also some people who already own a NES/SNES Mini, and who understandably can’t justify purchasing yet another system to play the same games. For those people, the ability to add extra storage through an OTG splitter cable is an incremental non-invasive upgrade that makes a lot of sense.
And the other point is that hakchi makes hacking the NES/SNES Mini so easy that part of me thinks, why not?