The main issue with side b as a ledgestall is that it's finite and announces you're going to go up the next time. If you play around that expectation it's good but you have to be aware that it's a much stronger tell than a normal stall if you're going to use it successfully
pewpewu did a video about this invincible stall soooo long ago. But he didn't talk about the tech and reversal options, that part feels very modern lol. good stuff
I like to edge guard using reverse side B from ledge a lot. I first saw Rishi do it and I've also seen Zain do it a couple times. It's great for covering certain firefox angles while being a relatively low risk option and you can get good follow-ups from it to secure the edge guard like jumping back to stage and hitting a tipper F smash, dropping down for reverse up B, double jump fair since you still have your jump etc. it's a really underrated option IMO