I'd like to approach the investment standpoint from another aspect.
Second vacation home.
You might make money buy a vacation home, i.e. sell it at more than you paid for it. You might be able to rent it out during a year for more than the upkeep. But no matter how you look at it you are investing a lot of money, often on margin (mortgage), and are taking the risk of irregular return on the money at risk, with a negative cashflow base (you have to pay taxes, upkeep, and mortgage (if applicable), whether or not you can rent it out or not. You can then use a few weeks for personal use.
On the other hand - timeshare.
You won't (except in extremely unusual circumstances) make any money selling it. The money you use to buy it is write-off money (or should be treated as such). you also have a negative cashflow, as well (maintenance fees). But you have no more capital at risk than the initial purchase. In addition, you have no worries about upkeep, taxes, or utilities, it is all rolled into the MF. Furthermore, in expensive places, like Hawaii, you may find that the MFs don't exceed the upkeep costs of an equivalent vacation condo until you reach 2 months or more of timeshare intervals.
So, on an ongoing basis, as a vacation property, used occasionally, timeshares may be cheaper. (Of course, it depends on the timeshare and the condo. There are better deals and worse deals. YMMV)
Shrug. How do you view "investments"?