I'm trying to get more people to use E6000 so they will keep making it. I used to use Duro Liquid Rubber, which disappeared. For some time there didn't seem to be anything that would work until I discovered E6k.
Sure, gaffer tape is great. I've been using it since 1969 (as seldom as possible due to the expense). Yes, it is vastly superior to duct tape; not the same thing at all despite superficial appearances. It is so expensive that I avoid buying it whenever possible but if you need to hang lights (which is what it is made for) nothing else will do. Do you want to pay for a whole roll just to get enough for a few pieces, then have these rags attached to your bellows!? Bellows usually develop pinholes on the corners of the folds where you'd have to make origami things to do the job. What a mess, folding it on corner! What is it going to do to the way the bellows compress when you fold it up?
I'm just being difficult. I'm like that. But anyway, I really wouldn't use gaffer tape on my bellows. Maybe it's just me.