You are being tested. Which font are you most likely to believe? Which font is most likely to get you a big, fat click-thru? For starters, the behavioral research points as much hatred toward Comic Sans as the design community. Justification feels good.
Like most testing, you can throw asterisks on all of the research points from Yieldmo, but the results indicate that legibility carries weight. Rather than shoving 10 pounds of text into a five pound bag, stick with a simply message in a font that is easy to read and your mobile message will become much more tap happy.
As a side note, integrating dancing babies into your advertising will also hurt your credibility. However, a dancing Carlton will instantly improve your believability.*
*This statement is not verified in any way.