Yep, serious eats has a few videos on cutting that are useful. It only takes a couple minutes to dice an onion or shallot. Much less time than cleaning a food processor.

For sure. For small things, I'll definitely just use a good knife. For making things like stews, I'll probably fill the food processor 5 or 6 times with vegetables (it's on the smaller side), and then just spray down the hopper and the lid with the sink sprayer.