Regarding your edit, you might be ok with going on a multi-day hiking trip or family holiday while still doing some amount of work from your phone, but many of us think that's a bad idea.

Truly disconnecting from our work is necessary for our mental health. When I'm on vacation, I want to be on vacation, which means not working.

Again, maybe you don't want to actually fully be on vacation from work. I guess that's fine; you do you. But I don't think that's healthy for most people, and regardless of health, many people do just want to completely disconnect from work for some number of days.