My cellular iPad basically replaces 90% of my phone need. I can live temporarily without my phone, but definitely not the other way around. I even have a costly cellular plan to go with it. I don’t travel like a businessman, but cellular saves me so many occasions I can’t even count. You would not want to go back to wifi only if you use it extensively for a while, with the notable exception being your daily routine relatively fixed.
No. Wifi only model can’t get GPS location. It uses nearby wifi to try to estimate where you are. The more remote you go the less accurate it becomes, up to a point of no idea.
It can because it uses your wifi to know where you are. There is no GPS on any MacBook.