Although Fortnite is maybe the most popular mobile game at the moment, I think PUBG mobile isn't a bad game at all. It has good graphics, sound effects and it's realistic, unlike Fortnite.
Graphics and sound effects
I personally think the graphics of PUBG (PlayerUnknown's BattleGrounds) are better than Fortnite. The plane looks more realistic, people look like human and not like some plastic dolls and overall the world looks better.
The sound effects of this game are also like the real life: walking through grass or swimming, it sounds just like it's real.
In Fortnite, you must jump out of a flying bus in the beginning. PUBG makes it mor realistic: you are on a flight and have to jump out of the plane.
Of course I don't want to upset the Fortnite fans, I played that game too.
There are differences between the games: one wants a realistic game, the other wants a game which is really for entertainment.