Zac Efron and Dwayne Johnson getting to be ridiculous, over-the-top lifeguards, surrounded by beautiful people and beautiful scenery. Sure, why not. That Baywatch is highly self-aware helps matters a lot, consistently reminding the audience that it is completely absurd that a team of beach lifeguards are going around acting like cops. Somehow, despite that premise, it makes it not awful... though that's not for trying.
Efron and Johnson are the main reason is picks itself off the floor at all. I'll always be impressed at how good both actors comedy timing is. The rest of the lineup, though, are fairly inconsequential. The women don't get particularly useful dialogue or roles, so it's not entirely the actor's fault, but their story arcs just aren't that great. Ditto for the fat loser stereotype. He does what he can with the role he was given, but when a central part of your character is getting your dick injured you know it's never going to be a brilliant role.
Speaking of which, the comedy in Baywatch is hit and miss. Yes, there are some funny moments and decent lines, but it also gets carried away with itself. It's a first-pass script that somehow made its way to production and it shows. Even with the film embracing its campness and ridiculous 90s heritage, it frequently spoils things by being too blatant or too over the top. It's almost striving to be "so bad, it's good" but never quite gets there. The plot is stolen straight out of the show too, which I guess is a decent homage at least, but feels a little dull at times. A lot of that can be forgiven by the final jet ski chase sequence and some of the action is actually pretty great, plus the finale with the fireworks lands fairly well, but it's all a bit too little, too late.
Overall, I enjoyed myself. It's mindless entertainment and utterly missable, but you have a couple of hours to kill and you're a fan of either of the main actors or the original show, it could be a lot worse.