While it certainly does come in handy if you’re going to be using anyone else’s code in your project that isn’t in the standard library. There is a chance that they may have defined std to be something else.
Which could cause the development engine to become confused and either not work, or substitute your intended use of std in this case print out with something completely different.
Say it could be used to set values to data or something else. I’d imagine in a good compiler it would prompt a warning about STD (but if you have a huge project with multiple files and suddenly you’re getting warnings across the board tracking it down could be a hassle. In a bad compiler it may just go forward and god only knows what the output of your code would look like.