I see those things in traffic on trailers so people are buying them. The off road parks here have hills with trail sections that are so steep and sketchy you have to have a motorcycle to get up and down them. A side by side would lock you out of a lot of the trail system by default just because they are too wide. If you drove way up into the mountains you can drive them on the forest service roads, which is likely what the people here are doing with them.

Idea of what it's like here on one of the trail riding areas.

https://youtu.be/BqwTxKKbGFs