The way Vello/Masonry/Xilem are split projects is partially what got me interested in it (and in turn caused me to post it to HN), as well as the reactive architecture of Xilem.

I do believe a garbage collected interpreted language would work best for UIs. Something like Vala (for gtk) but with a runtime/vm.

python-qt has shown to be a very strong combination. My issue with such solutions is that packaging a python application to the end-user can bloat binary size.

I also think GTK should get some credit in that space, because due to GObject introspection it's easy to interface with GTK with any language.