Welcome to TeX.SX! Yes, there are downsides; never use align for one liners.
– egregAug 18 '13 at 13:44
If you're interested in learning more about various display-math environments (and, in the process, figuring out for yourself an answer to the question you've posted), I would like to suggest you follow the discussion at http://tex.stackexchange.com/a/40531/5001.
– MicoAug 18 '13 at 14:04
alignfor one liners. – egreg Aug 18 '13 at 13:44