I am 418 with half my gear having a hole. Benefit of running mythic bod is I can clear it within 3-4 hours, and probably get an azerite piece to scrap. A lot of these high end mythic+ players are spending 40+ hours a week spamming dungeons. With these dungeons the affixes don't really change anything other then longer boss fights, longer trash fights or difficulty for healers. I can't imagine running the same dungeon 100 times. Just imagine if they kept uldir as a raid for the entire expansion and only changing the item level that it drops every patch.