I think this is a net good in the long term. Even if you completely exclude obvious benefits, like being able to support more APIs than Safari, it forces Apple

I think this is a net good in the long term. Even if you completely exclude obvious benefits, like being able to support more APIs than Safari, it forces Apple to actually compete with other browsers and implement things if they start getting real market share. Not that you really should, but Safari has a limit of 500 tabs. Why? It's arbitrary. Safari doesn't support WebRequest in blocking mode, so you can't have real adblockers (just MV3 style content blockers, like uBOL). There are all sorts of edge cases too, like if you want cross-browser sync and extensions. Sure, you can totally run Safari with extension support, but extensions in e.g., Orion are shaky at best. The biggest claim that Apple made about this whole thing was that web browsers offered an attack surface increase as a result of giving JIT to other browsers, and they could be owned. Frankly, though, I would take a browser without JIT if I had a real adblocker.