Thise should reduce the artificial latency added to window manager
operations (like calls to some of Emacs' frame API, e.g.
make-frame-invisible) on the PGTK build of Emacs. This should mitigate
latency issues with childframes in general and packages that use them,
e.g. lsp-ui and company-box.
There's also a small chance 0.001 is much too low, and may cause
artefacting on especially slow hardware. More testing is needed.