The itch text editor, like the one I use for this post, adds lots of nbsp.
Is there a valid reason for this?
Because it has side effects, that are not visible at first glance. And I bet most people do not even realize what a nbsp is, or what it is used for, or intended to use one.
It happens mostly when copy pasting. A situation where the user probably does not intend to have such spaces, but would want normal spaces, as were present in the source, but got replaced by pasting it into the editor.
The obvious side effect is storage size, wich is important for those places where size limitations apply. A space is 1 character, & n b s p ; is 6.
(There is a weird bug on my system, where the font used to render nbsp appears to have zero witdh, so I do can see where those nbsps are between letters. Otherwise you need to inspect the portion of the site to see if a space is normal or nb)
Oh, and the code formatting in posts does not work as excpected.
& n b s p ; cannot be written here as code " " <- the code inside gets parsed.