Technically any USB connection should work and that is a technically correct answer.
The reality is the reason why many manufactures still choose to use mini USB connections on devices despite micro USB connectors being more common is 100% opinion based.
You say:
“I'm genuinely curious about it and find it perfectly on topic. Technical reasons are hard facts, not opinions…”
There is utterly no technical reason why one type of USB connection is used over another. Thus it is a fact that micro USB, mini USB, USB C and other connections could be used but for some reason they are not.
That “some reason” is not anything anyone here can answer because it’s clearly a manufacturing decision on the part of the manufacturers of devices such as external USB drives. And that is opinion based even if we knew the production/supply chain rationale because it is not a technical decision or reason.
And the closest to any real answer anyone can provide is either mini USB connectors are cheap or many manufacturers have invested so much into mini USB connections they don’t want to change.