I don't quite get it.
Every changing bag I've had, the two layers are joined at the cuffs. If you put the developing tank, film, etc inside the outer bag and not the inner bag, you can't reach the tank, as Valerie mentioned above. So you have to start over and do it right. This is a good thing. Learning to do things carefully and correctly is part of film developing work, otherwise you spoil the film.
I understand the fear of cutting a hole in the bag with scissors, although I find lifting the bag material with the off hand while cutting with the dominant hand prevents this from happening.
In a modern device filled world, the primary concern for changing bags and tents is not whether you use bare arms or not in the cuffs (they work both ways), etc, but remembering to take off any watch, Fitbit, or other device that may light up before sticking your hands in the bag.