The copy could state more explicitly that it does work as a regular phone with your number and SIM, but it is explained under the section "A No-Carrier Phone?":

The Librem 5 can be used in any of three ways:

- With a cellular carrier provided phone number, data plan, and WiFi

- With a cellular carrier data plan, and WiFi

- With no carrier, and using only WiFi

WiFi calling and VoIP calling will be able to be provided in WiFi or data plan modes. We expect to offer call-out, and call-in with phone numbers in all of these plans as well. If you still require a “traditional” phone number through a carrier and want to make unencrypted phone calls or messaging, it will be an option you can choose, but is not required (we recommend avoiding unencrypted phone calls).

I gotta say, I agree with that alex dude's reply on the supply being out of touch. The focus is all on the wrong stuff. I've specced out my own phone to build from scratch and these are the requirements I came up with:

    Make and receive calls

    Send and receive text messages

    Wifi hotspot

If you put a goddamn rad camera on it, it would be a winner.

>Will I be able to communicate from my Librem 5 to other phones?

>Yes, you will be able to make regular unencrypted phone calls to any phone number. You will also be able to communicate securely by using the phone dialing application and messaging application, that can run on the Librem 5 phone, Android based phones, and iOS based phones, and any computing device.

The FAQ is at the bottom of the kickstarter.