Is there a downside to MAS scripts?

Been seeing alot of posts about "is this build good" where people have a windows key as part of their pcpartpicker list or quote from a pc building shop, but noone in the comments mentions MAS (Microsoft activation script)? Is it not widely known that you can activate windows in less than a minute using them, or is there a downside that I'm not aware of? Personally used one a few months ago to activate wind10 and I haven't seen any issues personally so I don't really know