I could go into all kinds of what if scenarios for why jQuery should be updated, but for me it came down to wanting a Youtube overlay that automatically closed when the video finished.
Fancybox wouldn't allow me to use the YouTube API to detect when the video ended. So I started searching for a replacement and discovered Magnific Popup.
You can read about the development of Magnific Popup and what makes it different from all the other lightboxes.
Since Magnific Popup only works with jQuery 1.7.2+ I was forced to manually include jQuery a newer version of jQuery as well.
Below is the finished product (I didn't link to Unbounce because I don't want all of you ruining my A/B test :p )