Like I said before I'm not particularly good at the game, but I think that sometimes 5B will screw you over with note placement in a way that you can't really anticipate. For example, you hit a central hold note with square and then the other notes you need to play during it are on triangle/circle. You'd really want to be hitting the hold with right in that situation, but you wouldn't necessarily know where the follow up was coming unless you were on a low scroll speed. Not a problem with any other key mode.
Yeah, I noticed some charts in Respect do this. I think having to make like, over 500 note charts made peer review a little more challenging lol.