[JoelEinbinder]

It's been a few years since I was looking into it, so this might be out of date. But WPE is targeted at kiosks and places you might want to display web content but not have a full web browser. Igalia can sell consulting services to these companies, as opposed to webkitgtk which has a small number of non-paying users. So WPE serves as a place for more active development of webkit-on-linux while not breaking webkitgtk which powers the web browser "Web" on gnome. Things from WPE tend to slowly make it into the webkitgtk build eventually. It's all maintained by the same people.

Looking at https://webkit.org/wpe/, the first design goal is the one that justifies WPE vs other webkit ports: "To provide a no-frills, straight to the point, web runtime for embedded devices."

The other goals, like standards compliant and hardware acceleration, are there to differentiate WPE from non-webkit and ancient-webkit browser engines that people might use on embedded devices.