There's plenty of reasons to not use that platform:
I don't like its interface. I don't like its organization. I don't like their Vortex client and I don't like having to keep up with mods manually to have them up to date, either.
Steam Workshop support would spare me from every single one of these things, so I'll gladly use it given the option.
All of this. Steam Workshop is vastly superior to vortex
