It is not forgettable for me but I think for the general public yes. And Beyoncé herself has yet to perform this song in full. So yes, it's forgettable.
Check On It is probably one of my favorite Bey tracks ever. I can only name a few tracks better than it (Crazy In Love, Irreplaceable, Single Ladies, Sweet Dreams) but as far as the public goes, it seems to have been forgotten, unfortunately.