I'm on the opposite end of the spectrum I think where I'm very comfortable learning and understanding algs... I'm barely sub-20, but I DO find that knowing more helps me deal with the scenarios I'm not as comfortable with.
I SUCK at the G and N perms. They totally destroy my LL. SOOOO I'm learning COLL because I understand how to do edge control on the last CE pair insertion. I have done the G perm a gazillion times, and I know I need to practice it more, but in a solve "where it matters" if I can avoid it to keep my times down, I definitely will.
Knowing more algs for me, is simply a way of brute-force solving.
I know full OLL and full PLL right now, as well as a slew of F2L tricks... And I know practice will get me the rest of the way but while I get there, I'm very content feeling as though I'm progressing somehow by learning more algs
Once I get up to 200 algs though... I can see how that would be silly to try and remember them all successfully. I do have to say there's only 2 OLL's that I ever get stuck on and I just have to do them slowly.
(Sidenote: I find playing on hi-games.net really helps me remember my algs too. Makes me think about them instead of blindly applying them)