Design reasoning behind global config

I have asked this in the bytecode alliance zulip, but haven't gotten any answers. Maybe here is a better place

I am having troubles understanding the design of the wkg. Specifically why is it not possible to define registries in the wkg.toml. lets say for my plugin system, I have an arbitrary wasm oci artifact published at ghcr.io, how can I use it as a dependency in the wit? I am very likely missing something, but it seems that currently it requires you to specify custom registry in global config, which makes project not portable? you can use wkg --config option which points to file in the project, but then you have to use this option every time you use wkg which makes it feel like a workaround