I worked on optical sorting project that use cameras to scan many 1000s of small berries a second and you had around 10ms to extract each berry from video stream, calculate the center of object, decide if quality is good enough and schedule air stream to shoot in particular time to so it gets shoot out in exact time. Good luck trying to do that on Arduino type of board.

Industrial and industrial IoT is one of the use case for these kind of boards. These machines are not produced in high quantities so finding existing modules saves a tons of R&D budget.

Any camera modules you might recommend for such tasks, ideally compatible with the nano?

I can't remember the name of vendor, but they were from some niche manufacturer of professional machine vision cameras from Germany. Each of those cost few 1000s euros.

Almost anything for industrial use cost you a leg and then some. If you want to experiment with CV at home I would take a look at that high quality camera module from RPi.

Is the HQ camera module any better than the Veye Starvis (imx297/307/327) module?

Aside from being a third party module, they do quite well with low light situations -compared to conventional Raspberry Pi camera modules.

Blueberries?

Some applications require high speed inference, to be able to run segmentation and classification at high framerates

Not to mention doing other accelerated pre-processing & processing in addition to inference at the edge. There's certainly a use case for the Nano over Arduino, RPi, etc.

If what you are using is good enough than this might not interest you. Isn't that obvious?