Other than being a proprietary OS that's getting more locked down every year, its disk performance is trash.
I’m not watching a 31 minute video on X to figure out what this is about. Theo is another influencer who thrives on being contrarian, embellishing negative claims about things he’s not pumping right now, and trying to get everyone to ignore negative things about what he is pumping. I would not trust his judgment on topics like this without some third party benchmarks and deeper claims because the first priority of influencers in this category is to be contrarian and ride divisive topics. Being factually correct is secondary.
I use nix on macOS and any time it's making changes to /nix/store, the Finder and fsevents processes peg cpu.
IIRC his video shows fs-heavy ops like file deltions and pnpm install taking much longer on a macbook despite better specs.
Frankly, things like the lack of a universal cmd-c/v clipboard on linux has been 1000x worse for usability than slower bulk fs.