It's quite difficult to buy a USB-C cable that is not USB-C or Lightning on the other end. While USB-A on the charger's side with USB-C on device side is quite common and comes with a lot of devices that don't include a charger.
I couldn't find USB-C to USB-micro device cables at any retail store near me.
Ended up getting them off Amazon.
My transition to all USB-C is also much slower than it could be, since you can't get 6- or 10-port chargers that are all USB-C. iirc best I've seen is 2x USB-C and then 4 USB-A.
Use cases:
- my embedded dev boards are all USB-micro (sometimes 2x of) and worse, USB-mini or USB-B. setup for dev on the go from my MBP now is a foot-long USB-C to USB-micro.
- charging older Kindles, bike lights, etc