When I was little I used to eat crabapples too. Kids have an amazing tolerance for sourness!
The difference between apple and crabapple jelly is fairly subtle. Even though they're super-sour when raw, you have to add so much sugar to make the jelly that it comes out fairly similar to apple.
I was just making wild raspberry jelly this weekend and I would have loved some crabapples to put in it. They have so much pectin, and would have given a nice translucency to the jelly. I love the golden colour of yours, by the way. I remember it being slightly pink too, so the different varieties must give different colours.