I've never broken a chain or needed a chaintool for myself on a ride either...but on at least two occasions in the past ~5 years I've been on a ride with someone who did need a chaintool, and the fact that someone (else) was able to produce one and be the hero has convinced me that it's a valuable tool to carry.
Especially if you like being a hero. 'Cuz, y'know, the hero doesn't have to buy beers at the end of the ride
Actually now you mention it, on exactly two occasions in the past 5 years I've been on a ride with someone else whose chain broke, and neither of us had a chain tool. The first guy had ridiculously worn chainrings that had basically stretched the chain until the links came apart. The second had just put a brand new 10sp shimano chain on without using the special joining link. Both of them deserved to have their chains break, but of course I still had to limp around with them for ages until they found someone to lend them a tool... For which they guiltily bought me beers in any case...
