Better phones would be designed with upgradeable modems because the phone would be useful for longer than the modem is, but anything with WiFi can be connected to a hotspot.
I'm kind of surprised that isn't more popular in general, because the hotspot lets you connect all your devices with one plan for <$10/month if you don't use a lot of cellular data, e.g. because you mostly use it in your car and spend most of your time connected to some other WiFi.
I'm kind of surprised that isn't more popular in general, because the hotspot lets you connect all your devices with one plan for <$10/month if you don't use a lot of cellular data, e.g. because you mostly use it in your car and spend most of your time connected to some other WiFi.