So, my reason for using slide film isn't about projection at all, but about the "feel" of the colors, ease of scanning, and the more accurate rendition.
This, but I like projecting too. I shoot slide film because I drop it off, and when it comes back I have slides. They don't need scanned, printed, or color corrected. I don't have to feel guilty about not scanning them or printing them. It's a black box-- exposure in, slides out. For me, color is about snapshots and vacation photos. Slide film does this perfectly for me.