mental steepage, don’t waste it. that is: when you soak your brain in particular field for years, you become much more effective at working in the field and finding new ideas related. this is extremely valuable and can potentially separate those who can and those who cannot in a given area.
It also can’t really be faked, I don’t think. There’s a sort of loading-into-RAM that happens that uniquely positions you in a way that can’t be approximated by someone just beginning to think in a certain area.