I agree desktops are best, and they are what my kids started with, but there is a lot of pressure to give kids phones.
For example, where I live, the cheapest (monthly) bus tickets require an app, so kids need a smartphone to get to school (or their parents have to pay a lot more for daily tickets).
There is a lot of social pressure on the kids too. There are lots of activities that have either moved online or are organised online. Lots of ways to get left out.