There is "just to trade" and "just to trade for this one, specific thing."
I'm not a huge fan of the former, even though about 40% of my portfolio is exactly "just to trade". In particular, I would dissuade someone brand new to timesharing from buying just to trade. Even in just the 15 years I've owned, the third party exchange landscape has changed significantly, and generally not in favor of the individual trader.
But I have seen people try to do the latter over and over again. It never seems to end well. For example, those of us of a certain "timeshare age" remember the "winter SW Florida" threads (though those threads might have been Over Yonder). There were also a number of people who were buying things to trade in RCI for DVC exchanges, almost right up to the day DVC moved to II. In fact, I remember saying buyer beware in one such thread, literally weeks-to-months before the change.
TL;DR: It can be a good idea to buy a strong trader for a particular exchange in general. That strong trader can be used for specific things, often with good success for many years. Buying only for those specific things? Much more of a risk.