It's horses for courses when it comes to punch & die sets. I didn't get any for the longest time due to their high cost. But once I invested in them, I found them indispensable.
One of my first uses was to make hex bolts to cap the open ends of a metal track set. The round punch set made washers for the bolts, and then I was sold. I see it this way: If a tool allows you to perform a difficult task quickly, it is worth it.
I bought a round and hex set made by Sintec from Italy. I got a Waldron set for larger diameters, but I don't use it as much. I think the plexi shield is ridiculously flimsy, and have seen many sets with broken shields. I also have a beading tool set from a Japanese maker that makes the teeniest round head rivets, small enough to do buttons on a 1/48 shirt.
And this is my little friend, the Asgardian Modeling Hammer of legend, Mew-Mew.
I really DO use it! But all it takes is a gentle touch. Gentle.
But as I mentioned, horses for courses. A lot of modelers can get by without them, but if you scratchbuild stuff, they can really help.
And if you have the tools, you can make stuff for your friends! I made some big nuts and bolts for a friend's Ork Stompa model which came out crazy cool, in part because of the bolt detail.