not very well. I mean, I've used them to generate specific patterns for interfacing with remote control circuits when a micro wouldn't be fast enough, but you'd still need a clock source and there are much better choices out there, even though it would give you a TTL (actually, HC) compatible output, but there are much better choices.
You can generate sine and triangle and probably others from a square wave, so long as you dont want to change the frequency, its a technique sometimes used when you want an accurate frequency as you can use a xtal as the source, its not seen much these days as the dds has become popular.