Don’t always think of slow riding as junk miles.
I’ve got a mate at work that’s a cat 2 roadie, which is a very good level obviously, and he decided this year to give it a proper go to achieve cat 1 status. Anyhow, all the fitness tests etc done, guy tells him to bin his commuting as it’s junk miles. He commutes very quickly, about 30 mile round trip daily.
Apparently he doesn’t do enough long slow riding, emphasising the slow. He rides everything at training pace, so he has no base miles in him, which affects his stamina. I’m no expert, and someone will no doubt be along in true STW stylee to say I’m talking pish, but I’m only the messenger.