One of the points of Lyre was to have truly open software, and hardware.
Something anyone with the source code and schematics could whip up on their own home desktop and fabrication table.
Using cellular phones defeats that entirely.
Now, before anyone rushes to say "But Android is open!", it isn't.
There is a project by the name of Replicant that aims to replace closed vendor binaries with open alternatives, but the outlook for this project is truly bleak. Off the top of my head there isn't a single device that isn't functionally crippled in some massive way.
But the main thing is the hardware. Using phones, the project cannot evolve as freely as a project like this should.