I think for phone calls this only works on Facetime and for calls maybe only on Wifi. SMS syncing is true. But if you have a phone and you're out and about you

I think for phone calls this only works on Facetime and for calls maybe only on Wifi. SMS syncing is true. But if you have a phone and you're out and about you also need mobile data, so would otherwise need a second mobile plan. Or to swap the SIM over, which was easier with a physical SIM, more difficult with eSIMs.