Honestly, how much bother is it to have a couple of small monitors? Especially as they are likely to be MUCH better sounding than any internals? And easier to place where they won't feed back if you want plenty of vocals in the mix...

Bottom line is, it's easy to add a couple of monitors. But you can't add an extra 15 notes to your arranger when you feel like it. You DO play the piano, don't you? Personally, I CANNOT play pianistically on a 61. But a large percentage of all classical music and most rock and pop piano stylings can fit a 76.

I find it amazing what so many of us are willing to do, and what we are willing to lose, just to have two crappy speakers and a slightly lighter load-out