I just got done finishing a 72x72 quilt top doing just this very thing. For me it was a very necessary antidote to the OBW I've been working on. I love those quilts but to me, all those darn triangles feel very fussy and stressful and it takes me forever to get it all put together, so the unstructured fun of a fast, scrappy crazy quilt was (ironically) just the ticket to keep ME from going CRAZY! LOL
Funny how my scrap bin doesn't really seem any lower, though. Guess I'll just need to start another one! I'm only MAYBE 1/5th done with the OBW top. Probably more like 1/6th. Urgh.