WWE still is not sure what they want to call the new tag titles and women’s title on Smackdown so they’re “Smackdown” titles for now. That name is not final and the edict was put out a while back to not have "Smackdown" written on the faceplates. Vince McMahon hasn’t made up his mind on the name and they may end up being called the “world” tag and “world” women’s titles with Raw have the WWE tag and WWE women’s.
There has also been some consideration to changing the Raw tag and women’s titles to being “Universal” championship to match the heavyweight title and Smackdown’s tag and women’s being “world” in that scenario as well.
Clearly, names of the titles were not finalized prior to launch so they debuted as Smackdown belts. The name could even end up sticking but it really underscores the indecisiveness when a final call could not be made before the belts premiered on television.