I'm pretty sure I've heard it all before, and frankly, the whole subject gives me the willies. I've read a lot of this stuff in the past and it's all about determinism, quantum randomness, etc. All very Laplacian and, in my opinion, beside the point.
My point is that each of us comes equipped with sensors and a decision making machine that takes in data about the world and makes choices about what to do next. As I mentioned before, whether you believe that old decision maker is almost purely deterministic or somewhat affected by quantum randomness is beside the point, because in either case, one datum that affects those choices is belief in whether we can really make such choices. There is every reason to believe that fatalism, or its absence, plays an important role in the choices people actually make. This is one of those self-referential loops that bedevils even math and logic.
Mostly, I think, disbelief in free will is most useful as an excuse for bad behavior or moral or intellectual laziness. In any case, if you find yourself bringing it into the logic of any decision you are making, you are probably just confusing your brain.
Those brains we come equipped with are a kludge of parts originally designed for much smaller brained animals. We still have the same fight or flight, feed and fuck instincts that served our remote ancestors well. The biggest difference we have from them is the over development of the front of the brain, and its main job is to weigh the consequences of following those instincts against desired longer term outcomes. If we feel tempted to invoke "free will doesn't exist" in the course of any decision making, chances are its really just a way of telling you frontal lobes to buzz off.