Heatmaps are probably the weakest observation tool from the rest of features in VWO - we've been able to identify extremes of where clicks happen, where they don't, and where clicks happen where no link exists. That is the extent of it.
Scrollmaps have been more important, as they show "heat" of percentage of visitors that reach a certain length down a page. Our site has lots of content that we prioritize on the page but ultimately want to have impressions for all sections. VWO has allowed us to test for "scrollability" of designs, ensuring that visitors consume the content we put on our sites.