As a software developer focusing on web stuff, more and more of my peers are using Apple products to do their work. The more familiar the developer pool is with the MB, the more malware/trojans/viruses will come out specifically for that. Even if marketshare remains fixed. iOS development has really increased this in particular.

Assuming you're safe because of one fact, is a bad security practice. No one is 100% safe in computing, just like in life. It's all about risk REDUCTION.