The superfluity of free-will

Kevin Drum muses that a positive, concrete demonstration that free-will is an illusion will drive us all to despair and mass-suicide. That's almost as silly as saying since physics proves that all seemingly solid surfaces in fact comprises of tiny atoms suspended in space, we should be afraid of walking around in fear of falling through. Why fear the implications of something theoretical if your ordinary existence contradicts that implication every day?
Say if scientists did manage to build a machine that can account for the position of every atom, every neurological impulse, every piece of information about our present so that it can completely predict our every reaction, our every act. I would call that a machine that looks into the future. Not a machine that destroys my will to live. I might prefer not to look into the machine, for the same reason that I do not look to the back of a book for the ending before I'm done with it. But just knowing that the machine have this ability would not, I don't think, make my life meaningless. The big temptation would be, as with a time machine, to peek into the future and change things about the present to avoid mistakes. But I think we've all seen enough sci-fi movies to know that this strategy would be, on the whole, a bad call.
Julian Sanchez gets it exactly right on this occasion:

Free will, it seems, is a little like God in this respect: Believers often seem
to think it's so centrally important that without it, life would necessarily be
meaningless. Yet those who don't believe seem to get on just fine