Don’t listen to what he said… But SD cards are generally not very reliable. They might be fine they might die on you silently after a week.
Higher quality ones are better of course, but the quality of flash in SD cards varies wildly. I wouldn’t store anything on an SD card that I don’t already have a second copy of somewhere. (If I want to preserve it and it would cause problems for me to lose it)
Note that isn’t illegal, it just means the company doesn’t get to get out of paying unemployment when it happens. And that’s only if someone is willing to challenge them on it.