The holiday season (I'll save my defense of using that phrase for another post) is a time of rampant consumer joy in the US and most businesses want to take advantage of it. Many B&M stores deck the aisles with lights, trees, and Santas, and many online retailers do the same to their sites. Now I see nothing wrong with capitalizing on this to increase my business but I think you should do it in a way that preserves your brand imaging.
Here's an example from my shop this year. My usual banner:
my shop now looks quite festive and wintery it's still quite clearly consistent with the visual branding my shop uses the rest of the year.
So go ahead and show off your seasonal items, change your banner, welcome Santa to your shop, but keep it clearly your shop not another random holiday site and stand out from the crowd.