Black has winning chances, white does not. It's a little bit of bad form for white to be the one to offer the draw in the first place.
As far as refusing it, I'd only get annoyed if the opponent were taking an irrationally long amount of time, but otherwise play it out. For example, in this position as white, I might not want an agreed draw if I wanted to work on my drawing technique in that endgame.
See annotations moves 51-52.