I love the idea of it being optional. I can understand why many would want date functionality, and I can even envision using it myself in some cases.

All that said, my primary reason for using Workflowy is it’s simplicity. It’s interface is about the cleanest I’ve ever seen for the amount of functionality it has. I love that it is minimal, so personally, I’d rather not have that functionality at all than have it start to clutter things up.