The switch on the pinephone is for the power to the modem. All a bit fiddly, but it works. Cost difference is big too!

The pp's disadvantages is seems a little fragile, h/W switches under rear cover, battery life maybe 2 days on standby, camera not very good.

Advantages: price & availability, easy & inexpensive to repair. Open source modem firmware. Pp pro is more expensive. Both can have cover keyboard as extra, & can work well as desktop with adaptor.