Aren't those just web apps running inside a webview widget? What's "native" about that? (but tbh, at first glance this Hyperview thing looks like it's just re-inventing web browsers too).
I think the key idea is not the renderer layer, but the concept of DSL so that it can run on multiple platforms natively.
To go back to your question. WeChat actually has two sets of renderers for mini programs, one based on webview, and one based on native iOS / Android components. But you are right that most mini programs are using mostly webview to render, with only a few things being natively rendered.