A Simple open-source Phone programmable with Arduino

It is not really a phone - it is more like a Wifi connected device which makes all calls over VOIP. There is no GSM connection and therefore no SIM etc. I like the project but calling this a phone is inaccurate.

If a GSM module is also included, this would be a lovely device to have. Also, would be nice to have a much larger screen.

I don't think that's fair. Phones used to be connected by wires, then there where a few satellite connected phones, and nowadays most are connected by cellular. But they're all phones because that's what we call a device used to connect and talk to people at long distance using a registry of numbers or names. This one connects using WiFi, which is unusual. But it has the same basic functionality of being a phone.

For the last 10 years the default definition of "phone" (unmodified) has been "cell phone". These days if you want to refer to a landline you call it that. If you want to refer to a WiFi phone you call it that.

The primary function of a "phone" in the modern sense is to allow people to reach you (by means of SMS or voice) wherever you happen to be at the time. Something that doesn't meet that need isn't an unqualified "phone".