Also, what counts as "work" might not match up. For some people, "working" means just sitting in front of a computer for a set amount of time. Especially with intellectual work, it's hard to balance the amount of time thinking about how to solve a problem, vs. actually implementing the solution. For all we know the person who says "you just have to have discipline" spends 95% of their time falling into random rabbit holes, and 5% actually coding, and so never gets anything done. Or otherwise, maybe they spend 99% of their time coding, but never actually stop to think about ways to solve the problem better.

I'm not saying that productivity tools solve all your problems, but I find that it makes it easier to choose how much time I spend on each thing.