[nap]

are you talking about something like this?



while most mudders do not use inside corner bead (from what I have seen), I have been on some jobs where it was used. When I asked why, the taper said it makes for a really nice straight corner (and it does). While some guys can do a great job with just tape and a flat knife, some guys use inside corner knives, and some guys use bead.
trust me, I'm the guy that would be using inside corners because I don't do enough mudding to get really good at it. It helps make up for my lack of skill in the discipline.

 

[nap]

OK, I guess that makes some sense I would normally recommend using an inside corner knife regardless. Even though many pros discount them, they work very well, especially if you don't do taping for a living. Personally I don't think the corner bead above would save much time because you still have to embed the tape the same way and you still have to use the corner knife the same way. Really the drywall itself should be straight, and the above isn't much different from just a piece of paper tape. But whatever floats your boat!

the way I have seen it done is with a straight knife into the corner from each side. No corner knife. You don't need one because the bead is the corner.