I find all kinds of random things already don't work on mobile Safari - the web is effectively unusable without an adblocker, and over the past few months I've seen an explosion in the use of sites using "AdShield" which, if they detect ad-blocking, breaks websites (and lies to the user about the cause). Desktop browsers are able to handle this still, but on mobile Safari it just results in a bunch of the web being broken.

I do wish it worked more like GrapheneOS, but the other protections outside of web browsing seem to make it worth enabling lockdown mode. Personally, I'm only reading articles on my phone's browser so I'd wonder if I'd be fine with disabled JIT and crippled decoders.