That video was just to show off the CG, sasook isn't a Bowser main and I'm sure if he could post here he'd tell you that he isn't very good with him.
In any case, it isn't a 0-death, but Bowser only has one recovery option, and that is to drop low and sweetspot the ledge with up+b. This is similar to the Falco CG on Link etc in that it is escapable by DI and teching, but if the Falco doesn't spike and you attempt that, you die anyway.
I don't think it's a huge factor in the match-up, but Bowser is very easy to grab compared to a lot of the cast. Many of his moves are laggy on shield and can be shieldgrabbed, even some moves that many other cast members CAN'T.
Bowser is for whatever reason dash attack locked and chaingrabbed by ZSS for a wider percentage window than any character, which is hilarious. Bowser can be dash attack locked at like 25% until 70%+. This is kind of a big deal IMO because it makes mistakes near the edges of the stage very bad for Bowser, especially laggy mistakes. Dash Attack is a fantastic punish in this match-up.
Bowser's claw-hop camping is annoying because ZSS is really tall. It is especially annoying on Battlefield, but the stage is still better for ZSS overall because Bowser is really big and easy to juggle through platforms. Uair strings on bowser are very effective.
Of course Bowser will die late. His recovery is often underestimated; generally speaking you won't gimp a Bowser that is recovering smart unless you manage to footstool him during his second jump (not super likely) or he doesn't sweetspot with up+b. I recommend keeping a kill move fresh (probably fair) or we're talking 200%+ deaths from Bowser. Pressuring him offstage is effective, but only if you predict his second jump. I don't think any aerial but uair beats his up-b.
Bowser can exploit ZSS' bad shield pressure game because up+b out of shield is really ugly. As a result it is probably better to try to force Bowser to approach. This isn't that hard. Bowser's claw-hop camp game is effective but I BELIEVE is easily beaten with a simple usmash, repeatedly and effectively.
Fair is really annoying when spaced well, but I think dtilt beats it and is probably ZSS" best ground option.
I would give a large advantage to ZSS in this match-up at 7/3 or worse. Bowser's fat, lack of aerial options, mediocre ground game (even ZSS' is probably as good), and weakness to CGs, locks, and easy damage strings make this one of ZSS' easier match-ups.
