additional customisation of interface can give advantage.
additional options for hotkeys as well.
but for that you usually need to invest time to spend it in settings or get used to new hotkeys and interface.
some mods give advantage without any drawback.. like "no shake"
with ACU highligt you will never confuse sacu for ACU
i don't use to many of them to give more examples
But it is kinda more important that they make game easyer to play and more enjoyable.
While advantage from UI mods is not big and most UI mods are available for everyone.
just like you can go to settings and adjust stuff for yourself, you can go to mod vault and setup UI mods for yourself