I would probably try out a couple if I was bored, but I prefer coming up with my own character and having the companions with their own stories.
I used the mod to check out a bit of Astarion's origin because I wanted more insight into the character. But I got bored quickly not playing my custom character and abandoned the playthrough.
Same here. I wanted to find out what in SH's box but quickly got bored. What annoyed me were the things Shadowheart was saying to herself when she hit a ground trigger. It was playing someone else's character and just wasn't invested in her -- wait, I didn't want her to say that . . . I became a viewer instead of a participant.