I've done them for various reasons, all when going solo (or in one case intending to go solo and DS and DIL were able to join me after I booked).
1. As others have said, was staying in a deluxe and didn't want to pay for arrival night for a short time in a deluxe.
2. Rented points and couldn't get all the days in the deluxe I wanted so split mod/deluxe.
3. Just wanted to experience AKL (ended up in villas but that was just because it was actually less) so did a 2 nights AKV and 3 nights BVW then needed an extra night but booked BWV through Orbitz so Disney couldn't extend stay, had to book last night at BWV and change rooms, 3 changes that trip.
They are not as big a deal for me as others since I drive down and can pack two bags, leave one in the car, drive to resort two and just grab different bag. I don't even have to leave my bags with bell services at resort #2 since I can just get them from my car when I'm ready to go to my room. The only exception to that was the AKV/BWV trip, which was the one DS and DIL joined me on. DS didn't want to deal with lugging bags from car so we valet parked instead of self parked and left them with bell services. When I'm solo it's usually just have one bag and it's wheeled so taking it from car to room is no big deal. I've never had any problems with MB, but I have an AP which might make a difference. I've also never had any problems with booking FP, even the trip where DS and DIL were along they didn't have APs. They didn't get their tickets until after 30 days out so it wasn't an issue and we rarely book them more than a week in advance anyway. I never feel homeless as some people will say, I get up early on move day, which I do anyway, I'm old I don't sleep. I check out of resort 1, drive over to resort #2, usually around 7 or 7:30, check in. The room has only been ready once. Go to whatever park I'm doing that day, go about my day until I get the text room is ready. I rarely go back to my resort when it's ready unless I'm just done with that park for the day. I've done it for a trip that was only 4 nights, 2 nights POR, 2 nights OKW (that was one I couldn't get all the points at one resort and it was so cheap to rent the points and split with a moderate that the moving wasn't a big deal).
I've found I actually enjoy doing it so it will probably be the norm for me when travelling solo.