Interesting question, I assume this varies widely depending on the person and circumstances. I'm in a unique position, perhaps: I am the eldest child and bought my own points earlier this year at RVA. I used my 2019 "free" points to spend a long weekend with my parents, spouse, and siblings at RVA and they all loved it (this was my "welcome home" booking, pre-Covid). It prompted my mom to start looking into DVC herself. She was going to go resale but ultimately decided to pay more to get the current direct incentives and AP discounts since we all go a couple of times a year. Part of the decision was that in 25ish years when they might be too old for Disney (I don't think 80 is too old for Disney for the record!) my siblings and I could keep enjoying the points. I'm a big Disney fan so I certainly won't mind having more points! Another thought was that my siblings and I might get together at WDW and see each other more often than we might otherwise.
My sense from your message is that your children are young so it's hard to tell how they'll feel. Nobody can predict the future, but consider that they don't
have to keep their contracts if they don't want to. They can sell them and get money instead. But maybe they'll keep them and love having them and maybe they'll sometimes plan vacations together and see each other at WDW...
I don't know if that was at all helpful... good luck whatever you decide!