Staying on-site, you can go back to your hotel and still feel like you are "in" Disneyland.
Just my 2 cents!
~mm
My own 2 cents on that subject is that unless you're at the GCH, or unless you're always in Tomorrowland when ready to go back to DLH, the walk back to your onsite hotel can rival the walk back even to hojo's (let alone a closer hotel).
I'll admit I'm not that much of a fan of DTD, but especially b/c of their curvy paths (I like a straight path with only one way to choose to go, lol), the walk back even to DLH was obnoxious. And since during our Paradise Pier stay I hadn't figured out the shortcut through Grand Californian, the walk back to PP just bugged me to pieces! So no matter where WE have stayed, we haven't gone back to the hotel for a swim break (or any break...my poor DH and DS, torment them so and they get so cranky! I swear I'll do better on our late May stay at hojo's), mainly b/c the walk makes us nutty.
Also, the value of onsite, well, it isn't a value to me. Not when I get get 20% off hojo for having an AP, or the ent. rate, or get the Anabella for a good rate...really low cost and pretty good, close-enough, h/motel are more valuable to me than *maybe* a bit closer depending on the route you take, for well over 100 and most likely over 200.
That's my 2 cents.
It's all opinion-based (well except for the actual distance to each hotel if you get the shortest route figured out). Good we've all got 'em!
Forgot something....for someone like me, I'd rather get a lower cost place and spend the money on fun things I can bring back home (taking magic with me), rather than give it all to a hotel that I have to leave after my trip is done. And I keep a nice little bubble around myself from hotel to park and back, so I try to keep myself "in" disneyland, even if my body is not, LOL).
OK, I'm sure there are more on-point things to say, I just don't have any now so I'll shush.