"The problem with not having the .com of your name is that it signals weakness. Unless you're so big that your reputation precedes you, a marginal domain suggests you're a marginal company."

I'd say there's a few major reasons: protecting the name and signaling we're a real company to larger corporations.

For us, we also host websites that allows JS/CSS/HTML, so being able to put our assets on a separate domain helps with security issues.