It is always nice to have two releases just for the chance that you break one or for some reason it won't work right.
When I am done with mine I just strap it to one of the bow limbs so that it is always with the bow.
As for using your fingers, that is the way that I learned how to shoot a bow. But that was way before compounds and releases were available. But even with my first compound I used my fingers and it was a couple of years before I even purchased a sight system for it. I killed a lot of animals that way before I went "modern"