Do you mean for work use, or for all their computing needs? I’ve never used a personal computer for work.
Several of them don't own computers and rely entirely on smartphones for their computing needs.
It's frankly a worrying trend. Smartphones are consumer devices that do not allow the kind of automation, tinkering, scripting, and ownership that computers do.
On the flip side it means that I will be more competitive in the job market as I grow older than I was expecting.