Hello,
Can you elaborate about what that would be for ?

Well, upstream Godot supports Wayland.

• Fractional scaling support
• Waypipe support (this is the big one for me, tbh. I like programming on my laptop, and I'm not really keen on moving back to X11)
• Better integration with Wayland desktops

And I would also assume that Godot built without libwayland would be unable to output games that support Wayland.

I see.
Godot is constantly adding new options to its build process so it's hard to keep track of that.
It seems it tries to add Wayland by default now but like you said it requires us to download it beforehand otherwise we get that in the building process:

We should probably add the new access-kit they implemented for Godot 4.5 soon as well.

But at the same time, we are switching to a GDExtension soon, so we won't need to build our own custom Godot anymore. This kind of issue will solve itself automatically.