If the question is: is the song good enough that it should have been kept for the next album instead of going on U218? I would say good enough for an album most definately, but at the same time it IS the perfect song to add on a compilation, because it is poppy and will probably get some attention for U218, which is the whole point. Also, if they want to take a less-poopy direction for the next album, it's better if this one is on U218.
But obviously now that it's on the compilation that would be really silly to put it on the next album. It's out already!