Sure but it's still going to be slower than a native GUI library designed for GPU acceleration because you still need to implement CSS layout and DOM which are

Sure but it's still going to be slower than a native GUI library designed for GPU acceleration because you still need to implement CSS layout and DOM which are suboptimal by design. Maybe by the time Servo lands to mainstream it will be fast enough that it won't matter - but right now that's just not true - DOM is still an inferior platform for GUI because the performance sucks and that's not going to change any time soon - Servo isn't even close to complete yet.