Why Are Both mA and mV Used in Embedded Systems Component Interfaces?

Good morning all!

I am a bit confused. Why do we use two different measurements when it comes to interfacing components with micorcontrollers? Can't we use just one and the other would be obvious using the simple Ohm's law?
The reason why I am asking this is because in some configuration files they were both used and I couldn't understand why.

Thanks!