My parents had an in-ground pool for ~20 years in the north.
1. Fiberglass walls did not break down over 20 years despite drastic differences in temps and the pool being drained half way every winter.
2. Liner only needed to be replaced a few times, once because somebody came into our pool area and sliced it.
3. Sand bottom was fine
4. Concrete around should be reinforced. My parents replaced a ton of the slabs around the pool. It doesn't matter how much you prep the soil, the ground moves and whole slabs break apart. You can prevent that with the stress cracks, but eventually it breaks up.
5. Given this was a long time ago they used traditional chlorine. It worked fine. Yes, you're dumping tons of chlorine in. I remember the big 5-gal buckets of straight up chlorine concentrate that we'd have to pour in at the beginning of the season to clear out all of the algae and such. Then there was "shock" and such, the tablets in the basket filter...etc. It is *a lot* of work/money to keep it balanced.
6. As others said, for every person that likes it, another hates it (work, cost, safety, yard space, actual usage vs all of these). Consider this carefully since you're effectively removing a huge portion of the buyers market from your house.
If I had one piece of advice - get an auto cover. We just had a solar cover, which limited its use, but it is also a *massive* pain in the ass to open the pool up in the spring if you don't have it covered in the winter. Dredging up decaying leaves, worms, salamanders, frogs, voles/moles/whatever rodent...etc, was a *disgusting* job. It was horrid smelling.