It can be true in some scenarios. But bubble and hex have different ofensive type, wich makes them quite different not taking in consideration energy generation.
Also, this difference is so minor that you need 5 bubbles or hex to reach shadow ball, 5 more to the next one, and hex “outperforms” bubble in the race to reach the third shadow ball (in perfect scenario involving no bait or fast move desync). How many times that is going to make a difference in a fight? Not many… so it comes up to preference and what you need in the meta you’re in (coverage)
In great I tend to run hex (bar a remix that was infested with nido + 2 dark), but when I used jelli in ultra (old premier) I used bubble for coverage for the meta (talonflame, stun-g, a ton of darks) as it gave me semi reliable water coverage to add up in long fights, and because the nuke with shadow ball was already there. Bubble jelli got me to legend that season, so it was quite nice indeed.
Obstagoon, gunfisk, nidoqueen, scrafty and all that stuff are harder to fight withouth bubble, I wouldn’t call hex the “preffered fast move”.
Water gun and bubble have a bigger brother called Waterfall in this game, BB and Infestation do not, and that’s a pity