Honestly? When I do stay on property anymore (not often) that is the deciding factor.
It's really the only significant benefit there is, to me. I refuse to be stuck on Disney property anymore without a vehicle, so I don't take those awful buses anymore. I can get myself from place to place so much more quickly and easily than Disney buses can take me - I am shocked now at how much of my day was waiting for freakin' buses - I can go anywhere else I want, I can actually go to the store around the corner and buy a Diet Pepsi, LOL. Or late at night I can run through any number of places to grab some hot food, instead of eating vending machine junk. Oh, and...Universal. (Plus, I haven't gotten sick once while at WDW since I stopped taking buses...)
So really, the "benefits" of on property, until this MM+ nonsense, was really just EMH to me. If you actually got to the park before morning EMH, you can do half a park while most guests are just walking in, then hit the road after lunch when it starts to get busy. And evening EMH - the parks are so much nicer after dark, heck, for years this was the only way to see AK in the dark. And by the last hour, everything is usually a walk-on, even at MK.
If they do away with EMH, I'll never have a reason to stay on property again - unless Disney reaches out and makes me a Disney Mom and gives it to me for free.