They can be compared in the fact that both are really bad.
The genre is kind of interesting, but so far, every game in that genre was bad. Maybe a AAA Studio will make a good one later.
If those shitty games can get that much players, think how much a good game with the same idea could do.
Fortnite is a bit better than PUBG, AND is free. BUT being better than shit doesn't mean much.
R* already tossed in a BR mode with GTA V.