Songwriting definitely. People can learn how to dance and can be trained enough to dance well, songwriting is something that can't just be created, you have to have the emotions, the words.. its a lot more difficult to master and some never do.
Songwriting. For me, dancing is completely irrelevant in music. None of my top faves can dance.
THIS. I think dancing is overrated as hell when it comes to music. Songwriting is WAY more important. I enjoy seeing my favorite artists dance but it's definitively not the most important.
Songwriting isn't a necessity in music just like dancing isn't either.
You can be taught the most basic dancing and it be passable, just as you can be taught the most basic songwriting and it still be passable.
You can make a career out of both.
If you're performing, you're not really considered a "full package" if you don't dance. At the same time, you're not really an "artist" if you don't write your material.