My dad had an '88 or '89 Bronco II. He managed to roll it twice in the first 8 years of owning it. They were so rollover prone that Geico actually stopped covering them back in the '90s.
So this person putting it on those wide axles probably made it significantly safer.
This is definitely a temporary install to pass a vehicle inspection. Tires aren't allowed to extend past the fenders, so the kiddie pool fenders get them past that rule.
Lifted trucks here with super wide tire will either have a second set of stock tires/rims that they will install before they go and get a safety check, or they attach cheapo "fenders" that get pulled off immediately after the check.
I haven't ever seen kiddie pool fenders before, I usually see plastic landscape edging instead.