There are weight, bulk and comfort advantages of a TQ/UQ combo in a hammock. But thought/effort free and draft free experience don't go together in my experience. I don't think most folks are going to be able to thrash around in their sleep AND stay tucked under a "just wide enough for a hammock" quilt enough to not feel some drafts. If you don't move much, no problem. And many folks don't move much in a hammock, so it works out good.
But it is only in a Pea Pod that I never really have to concern myself with drafts, period. At least if it is fully closed, or with only a very small breather hole, OR if I have at least a puffy garment over my neck/chest area to block off heat escape from below my neck if I have a wider breathing hole, especially with wider, deeper hammocks like the Speer. Or of course, a very light TQ. But if the above conditions are met, I can have my hands under my head, or toss from side to back to side if desired, and no draft problems worth mentioning.
But some times I just prefer a separate TQ/hat/hood/UQ approach. It seems a less claustrophobic approach, and that is extra important for some folks. And it won't work on my bridge and or a netted HH, and is not optimum on all gathered end top loading hammocks. And some folks hate the Velcro. And it is probably too much weight for the warmer seasons. And it is not a dif cut, so there is a little more fiddle factor involved. Compared to the fool/idiot proof approach of just hanging a MWUQ UQ on a BMBH. So, learning to solve draft issues with separate TQs will remain an issue that must be considered for most of us.