I can understand not visiting parks but not staying at disney and choosing not to is very unusual I think.
I wouldn't save that, especially as they are DVCers. I would be inclined to do the same thing - why pay for a hotel when you don't have to? I would much rather use my points to stay in Disney and then do outside Disney things, than have to pay out extra for a non-Disney hotel and then other things on top.
Once you've been so many times, the magic does start to go a little and you do have to step a little step back from time to time. Our last trip in May, we didn't do much at all, but we had planned it that way.
We stayed in the hotel room - we had AKV with Savannah View, so spent a lot of time watching the animals, spent time in the resort (pool parties, quizzes, bingo, etc) and then went to the odd park here and there. I don't think we ever spend more than a couple of hours in a park, and we only generally went to the parks that we were having dinner at.
Don't get me wrong, we did ride the rides, but the two weeks were no where near as action-packed a holiday as we usually do. Even when we were in the parks, we spent more time shopping and pin trading than anything else. But it made a nice change, and means that our September holiday, which is going to be very different from our May trip, will be that much more exciting, because we didnt do much last time!
There's nothing strange with it when you go every year, especially if you go more than once a year. For those that are going for a first time, or a family holiday for the first time in 2+ years, then, yeah, it might be considered very strange. But for those who go every year - no, I can definitely see the appeal.