Reason: Leaf is a fan name. Blue is her official name from the japanese version of the manga.
The name Leaf isn't used in any official works or products. With no official source, (except as one of the 18 or so default names. It appeared for either gender but only in the LeafGreen version of the game) it shouldn't be used. The only differences between the Game and Manga versions of the character are their eye colors. The male protagonist in both the game and manga share the same tag, and a fan-name shouldn't stop the same for the female.
Nintendo claims she has no name, that it's up to the player. The character Blue in the (japanese) manga shares the same appearance (in later volumes), so Blue should be the tag for both.
I suppose we could do the alias and just use the copyright tags to distinguish. Most of the images under leaf_(pokemon) blue_(pokemon) appear to just be images where the tagger(s) couldn't decide whether it was the manga character or the game character. There are, of course, a few exceptions like post #958855 and post #343293. Of course, that's what the multiple_persona tag is for.
That said, just the fact that each version of that girl supposedly has a different name seems to be a poor reason to have two separate tags in the first place. I think the alias is a good idea, because they look almost identical (sometimes, they are 100% undistinguishable in fanart), which is important for Danbooru purposes. And this statement is notably true:
Algasir said: Most of the images under leaf_(pokemon) blue_(pokemon) appear to just be images where the tagger(s) couldn't decide whether it was the manga character or the game character.
Well, if we have that alias, then please don't forget to do the whole work:
