I had a large customer in the region who bought Motorola XTS2500's and XPR6550's. They wondered why they would not talk to each other. I explained that this is two different types of digital signal.
The XPR6550 is DMR compatible, the XTS series is not. However, in analog mode, they can work together.
So for interoperability, it is often wise to have some analog channels for those different types of hardware.