Jane E., that's what we've found works for us. Whenever I've/we've gone to WDW for just a few days (3-4 nights), staying onsite has worked out very well. With a short trip, the parks are everything. And if I/we had no car, it didn't matter.
With any longer trip (like a week or more), staying offsite in much larger accommodations was far better. We've had many times when an offsite trek to Wal-Mart, a pharmacy or a walk-in clinic was necessary and the longer the stay, the more the chance of that. So having our own car is more important to us on a longer trip. The drive to the parks matters less, with a car. Also, on a longer trip, everyone needs the added space and privacy. 7-14 days in a single hotel room is just too long, for all the kids & parents alike. Space, privacy, romance, luxuries and convenience (2 bathrooms, kitchen, etc.) are all better in a big villa. When we've paid for that, onsite, we've found that it was grossly overpriced, to us, especially if we're spending a lot of time at the parks and leaving that overpriced room/resort vacated all day!
Go ahead and try a shorter trip onsite. You'll probably enjoy it a lot! We like to add a couple of days onsite in a discounted deluxe Disney hotel room, to our offsite week. The pool areas are fun for our kids and we hardly visit the parks then. But everyone needs to see what works for them.
