It's the little things.  This device allows me to connect an external power supply to my Canon EOS M50.  I need this for the CharVi studio setup where I have the camera setup in a rig.  It's not hard to change batteries, but it's going to be way more convenient to not have to worry about switching batteries anymore.  Now it's always on.  Little by little... my CharVi setup gets better and better. :-)