Yes why lock yourself into one system when you can enjoy all systems and rent for less?
It gives you independence mainly. Also, you are not entitled to somebody else's benefits. The VIP benefits don't really apply to my habits personally anyways. I mainly only book Club Wyndham when the remaining inventory is discounted to all owners or when I need to book 10-13 months out. I also like to exchange into Saratoga Springs via RCI for MUCH cheaper than renting that same unit from a DVC owner. The RCI exchange is about $1500 cheaper for the week vs renting from a DVC owner. I live an hour from WDW so I like being able to just take a week in the summer time to enjoy the 5 pool areas at Saratoga and be a short boat ride away from Disney Springs. You may be able to rent for less for your habits, but it doesn't apply to everyone.
I rented off a VIP Gold TUG member last November when I wanted to spend a few nights in Daytona in a room that was guaranteed to be Ocean Front. If I used my own account, it would of cost me more to have a guaranteed Ocean Front unit, but that was a special circumstance where the owner hadn't used all of their points or guest certs because of COVID. But I wouldn't expect that owner to have points to spare every year. Obviously they bought their points with the intensions of using them.
The people who bought VIP did so because it made sense to them and they had the means to do so. After seeing how many boomers don't have enough retirement funds saved up and are having trouble finding a job because of age discrimination, it makes sense to me at 31 years old to just dump everything I can into retirement accounts (to maximize appreciation) while I wait for the housing market to inevitably crash again so I can finally become a homeowner, then dump whatever is left over into that after 401k and IRA contributions are capped. Nowhere in my budget is a luxury expense like a VIP purchase. I didn't pay for the VIP benefits, and as a millennial who has gone through 2 major financial crises in the first 15 years of my adulthood I never will make such a luxury purchase unless I was set for life, so I shouldn't expect to have access to VIP benefits. I loved and appreciated the Ocean Front room I got to stay in for cheap, but it isn't something I expect to have under normal circumstances.