Like others, I use it to set context. I can click on PC's profile and see which clubs he's reviewed, what his comments are on them, etc. He might be a bad example because he spells it out in each review, but if it were someone else I could find a common club we've visited and get a better idea of his perspective. That makes his reviews of clubs I haven't visited more valuable. The same is true of comments, it provides context.
I also will use it to find an old post with something, maybe a funny comment or nugget of info. I'll remember it was a thread by a user, then look at that persons threads, then find the comment.
I'll use it to go look at my own review history too.
Also, I agree with Rick. I miss having the # of reviews/# of places near a user profile in every review/comment. To me, that's much more worthwhile than the tagline stuff. Or at least worth finding a place to put it somewhere. # of trusts to me is still useless as the last time I looked there were still old "Self props" or repeated props from the same person being counted in that number.