Storage is cheap until it isn't.
On my desktop where I have something like 6 TB of NVME storage because I am a sicko? The only thing that makes me think twice about a flatpak is if I need to give it access to devices or significant parts of my filesystem (yay permissions weirdness).
On my laptop where I can have one drive and replacing it involves opening the entire laptop AND reinstalling Fedora (or dealing with clonezilla/dd)? Yeah... I very much care about just how much bloat I am dealing with. And, as the other person pointed out, flatpaks can balloon REAL fast.