Why a phone connected to the cloud PC is shit

This would be an amazingly trash experience over wireless so you would need to dock both because wifi sucks in most people's house AND because it would just constantly die.

Then it would ruin the battery to run it this way and on most user devices this is difficult/expensive to replace.

Many people have old phones that would perform even more poorly than average.

Your phone needs to be in your pocket and used for a million and one things not on the desk running a client to the cloud where you are editing an office document .

Oh sorry can't listen to my music as I walk around the house because I have to fuckin undock it.

No honey you can't use the PC its actually my phone and I'm running out the door. Let's undock it and fuck about and make your phone the client oh wait it doesn't work with your model for some reason? The sound doesn't work right? oh sorry gotta run out the door.

The efficiency argument and latency are in direct fucking opposition because in order to have acceptable latency you need to have a bunch of server racks near people which absolutely ruins the economics.

Why your TV as a screen is shit

Not positioned in a useful way or with a reasonable DPI or non-shit text rendering , nowhere useful to put the keyboard that is non-awful, pure voice input to use a computer is complete trash

Conclusion

Local clients that don't suck are going to be basic bitch small form factor PCs with ethernet and wired speakers because those things always work and always work well. If you don't fuck them up by running complete garbage they already run windows or linux reasonably well without issue. If you need a lot of processing power for AI you can run THAT in the cloud... which is already a thing.