I spent some time thinking on this and ways to expand a use or make it more themely, without totally removing the phones themselves. These ideas may be dumb, but it was just something that popped into my head.
Examples in this being, rather than making a new implant all together, develop it so the Progia can interact with pre-existing implants or cyberware.
Examples being:
A new App is introduced on the Progia called CyberLink, using this app allows your processor and phone to link up as long as your phone is on your persons.
With CyberLink activated:
Radio Implants can now function like a hands-free progia, allowing players users to talk on the phone.
Cyber-Eye attachments allow players to read text messages and use other apps on the Progia wirelessly.
Expanding on the idea:
Using this as well with a Passcode locking system to Progia, this would probably increase people holding progia on their persons, these phones having apps that link to their cyberware (because they may feel more confident to hold an app phone at that point anyways). Passcodes allowing players to lock their phones to secure information, but the implants allowing use of the phone even with the phone still on their person.
Emergent Loops: Phone Lottery
If phones did have a passcode system on them, this would give decker characters an option for trying to crack the phones (Similar to the phreaking discussion thread). Meaning you could score a phone with more apps on it likely, increasing a value of a phone.