...is that you are locked in a time and place to go on vacation. If you have loads of dough, that may not be true, but I don't have any dough, much less loads.

If it were in a locale that I really liked to go, I might consider it. I used always long to be in the Blue Ridge mountains, but it's gotten so crowded, I don't feel that way now. From the time my folks moved up there in the 80's til it had gotten to where they were unhappy with it except for knowing some back roads to avoid the horrible traffic.
Several times, though, we have rented time shares on a one shot basis and that has worked out well for us.