The positives you mention are valid, but for us it would be just like when we had a lake cottage....something to be done every weekend = work, not relaxing. One huge negative, at least in the seasonal-type campgrounds we've been through is that the people drag half of what they own to the site and it starts to look really crappy pretty quickly. Gotta have mountains of firewood covered with a huge blue tarp, the requisite ATV or two, leave all the kids toys scattered, towels hung between trees even after they've long since headed for home. No thanks. If the CG has stringent rules AND enforces them, that would be different, but not interested in looking at piles of work or junk when we're trying to get away and just chill. And agree on the word "Travel" vs "mobile home/cottage/whatever". We tended to mostly stay at 2 or 3 favorite CGs nearby, but different sites, different neighbors, really getting away.
When you say "buy" as in actually own the land under your trailer and surrounding is that the actual case or are you "renting" the land? Cost difference? Is it much of an investment? I know with RVing, nothing is a real investment, but are you spending more than you would for weekend camping, gas to get there, extras? Sounds like some math here could help sort this part out. Strictly personal opinion is that a seasonal would not be for us.