I'd been designing parts for years and honestly had no clue what happened after my models left my desk. So I committed to learning CNC programming properly, worked thru the basics on my own time, and wrote simple programs for a few of my own parts. The programming itself was useful but not in the way I expected. The real value came from writing toolpaths and realizing why certain features cost so much to make. Deep pockets, thin walls, sharp internal corners, all the stuff I used to draw without thinking. Once you have to plan how a cutter actually reaches into a feature, you start designing differently. That part alone changed how I model.
What surprised me is that programming only got me halfway. The bigger jump came when I started sitting down with the machinist who runs the parts I design. Watching setups, asking why my drawings annoyed him, learning how he reads tolerances on a print. Ten minutes of that beat a week of tutorials. So my take is the programming is worth doing, but treat it as a doorway into the shop floor, not the destination. Go find someone who runs the machines and buy them a coffee.