when is a phone not a phone

 A smartphone in theory is no longer a phone when the calling app is turned off. On my phone this was useful because you can't totally eliminate unwanted calls from registering on the phone. No matter what you set or change all calls show in the call logs as missed calls. Also, there is no direct way to disable the calling app, after all it's a phone. But the calling app can be stopped from running by removing enough permissions that it can't function, which makes it look disabled.

The phone still gets all other communication types, which is good enough.