I recently did an embedded job where we essentially used a mkrzero as our dev board. It saved us a ton of time on writing the firmware, since we didn’t need to wait for and debug prototypes. And the final schematic took way less time as well, since we could reference the mkrzero for things that might require guessing what the datasheets actually require.

There’s a lot to be said for having a commercial product with multiple revisions to avoid painful guesswork.