I don't think PW uses short tags internally, so using those is purely optional. I might be wrong here though...
Happened to have a PW site open, so I did some grepping (is that a word? should be..) and seems to me that you're absolutely right. No short tags found from core files.@Natetronn
, I'm trying to avoid getting all evangelical here, so I'm keeping this as short as possible: IMHO learning enough PHP to write templates effectively is much easier task than learning enough of most templating languages out there to do the same. PHP has very good documentation (php.net), wide user base (try googling pretty much any problem you're having and add "stackoverflow" to your query, it's rare to find a question someone hasn't already answered there) and there are many fantastic tutorials floating around. "It's easier than you think."
That said, I don't have that much experience with templating languages -- mostly I've used Twig and several in-company solutions, so I'm not much of an expert on this subject. All I can say is that after years of learning, fighting and cursing various templating languages and their shortcomings, being able to write templates in pure PHP is a bliss for me