This interesting thing about what they have in their example is there not all phones need to be 100% modular. that blue phone looks like a normal phone with only one modular point.
Best of both worlds
Best of both worlds
But the point still stands. I (as a manufacturer) could release a phone with huge customizability or maybe just 1 or 2 slots. Quite flexible
As long as the communication / power bus and physical size standards are ruthlessly enforced.