Interesting subject, Dick.

I've never done a whole set unaccompanied, but I've done the occasional floor spot where I was asked unexpectedly to do one, and didn't have an instrument (or couldn't borrow one).

I enjoy the challenge of performing songs I would normally perform accompanied, without accompaniment. As you say, you tend to fill in the gaps that would normally be filled by instrumental fills, by vocal ornamentation, or adjust the timing to remove the gaps, etc.

I have a small repertoire of unaccompanied songs for "emergency" use - for example, if doing a short floor spot and I break a string, and I don't want to waste time restringing because of time constraints.