The rooms should be the same. The main issues are cost (which you have noted already) and maid service. If you are booking through
DVC points, you will only get limited maid service (I believe it is trash & towels every 3 days, full service changing sheets and making beds every 7 days). While this seems like a small thing, it really bothered my husband enough the one time we rented points that he doesn't want to do it again. It drove him nuts to see the overflowing trash, and we borrowed extra towels from the pool (since ours weren't being replenished) and the dirty stack in the bathroom just got bigger and bigger. By day 3, it was pretty bad.
Of course, if the price difference is significant, that may be worth it. If you are booking a 1 or 2 bedroom (we were in a studio) then having the washing machine may make up for a lot of that.