In 2013, this site named Anthony Pettis' armbar from the guard over Ben Henderson as its choice for Submission of the Year. The criteria used to name it as such is as follows:
There are five elements that are most notable: the creativity of the submission; the ability to pull it off in a high-stakes, high-pressure situation; the lethality of the particular submission; the quality of the opponent on which the submission is being applied and the point in the fight or match when the submission is secured.
In other words, the beauty or complexity of a submission is worth acknowledging, but any submission cannot be divorced from the circumstances in which it was applied.