Compared to other 2.5* hotels on Priceline, the All Stars are an incredible bargain. You are right that most of the other hotels on the list don't even begin to compare. However, in the features that they use to assign * level, they technically do (no huge atrium lobby, no sit down restaurant, etc.)
I've gotten some excellent bargains on Priceline when travelling for things other than a family vacation.....translate that, It's just me and it doesn't matter where. Also for the cruise because I prefer to fly in the night before. BUT, for WDW, I'd be concerned about risking getting something off property, which would totally destroy the trip.