I thought about that option... But decided that the other way..... Attached to the hammock lets you separate the suspension rope from the hammock. AND lets you have a variable length piece of webbing for the tree, your choice how long it is.
If the tree is bigger than the webbing then some rope gets pulled into the loop around the trree, but doesn't really damage the tree the same as an all rope suspension since most of the pressure is still on the webbing at the "back" of the tree. This a weight thing since more 3-4mm rope is lighter than more webbing.
I think it gives the best balance of lightweight and flexibility without limiting your options too much.
At least that's the configuration I've been testing.
Nothing against other people making their own to attach to the webbing.