So, this mod is generally to provide additional charge spots for smaller robot areas with large numbers of active bots. In my games, I typically build robot areas that rarely grow larger than about 2x4 logistic areas as opposed to growing one single robot area to the size of my entire base.
In doing this, I generally employ 1000-2000 robots in one area. I add robots until I only have around 100 idle at a time (and remove robots if I consistently have over about 300 idle at once).
For me, this build pattern began to cause a problem - I could only charge about 30 robots at once across all 8 roboports, and all of my roboports would see big lines of robots waiting to be charged. Or, in other words, a lot of my robots weren't actually moving items for me, they were waiting for a spot to recharge. I could fill in a lot more roboports, but each one only offers 4 more charging spots.
This mod works as 10 charging spots for drones, but does not provide any other benefits that a roboport does, and can not be used without one.
Hopefully this explanation helps