"Tightly integrated"?

Agree. Apart from the repair aspect, and giving more hardware options to the general population, there is another angle too. Ara devices allow special purpose sensors to be plugged into a otherwise mostly ordinary and notably network approved cellular communications device.

As an example, you can imagine plugging in an infrared barcode scanner for logistics work. You avoid the clutter of a separate scanner that use unreliable nearfield communication to communicate with your logistics app and requires that the user handles two hand held devices instead of one. And you don't have to standardise on today's rare and rather expensive cellular devices with pre-integrated IR-scanners.

Ara allows small ISV:s to compete on such markets where producing special purpose hardware with integrated cellular communication today is prohibitively expensive. Now, worst case you have to develop your own Ara module. And if you're lucky, you can find a suitable extensible Ara module that fits your purpose off the shelve.