Qt5's QML2 is using V8 as the JS engine and an opengl es2 scenegraph, so it's actually quite fast. Depending on your embedded platform, you should still be able to achieve pretty impressive performance.
Umm, okay, can you point to anyone that mentioned that Qt5/V8 would be good for those chips? It's not like anyone came in the thread writing that "Oh, QT5 javascript scripting would be great for my 360 MHZ R1".
Oh and my CPU doesn't have any hardware OpenGLES acceleration. How should I work on that?
You shouldn't and nobody said you should. Just like nobody said it would be fine to program Big Blue with, or Arduino.