more tonal options, more varieties, etc.
Some people like that, some people don't - I mean, a great picture is a great picture regardless of whether it's in black or white, or colour. And that's all these pedals are really, different colours.
Of course, some people use wah-wah excessively (for instance) to cover up bad playing, but that's another story. Not all players who have lots of pedals are bad players.
For what it's worth, I prefer my fuzz-tone for soloing than I do the distortion from my amp. :)