The only people who use Realband are owners of BIAB. I think it is safe to say no one who wants/needs a DAW would choose Realband. It is much more limited than most modern DAWs. In my opinion it is quite clunky and sluggish with an old GUI.

It does have the unique ability to work with RealTracks BUT if you carefully craft your song in BIAB, using features like bar settings and freezing tracks, you are in for an unpleasant surprise when you open those songs in Realband. Realband will open your BIAB song but all those perfect frozen tracks will be lost and be regenerated in Realband.

To be fair I gave up on Realband long ago. So maybe they have fixed these issues recently. If so I'd give it another chance! But if it still works like it used to I'll pass!