Exactly this - I've bought a whole bunch of games I'm never likely to get more than a couple of hours into or even play at all but supporting the authors with a

Exactly this - I've bought a whole bunch of games I'm never likely to get more than a couple of hours into or even play at all but supporting the authors with a purchase gives a strong "I appreciate what you're doing" signal and, hopefully, encourages more of that kind of stuff (which only really works on indies, I know, but then those tend to be the people making interesting games.)