PeterBartholomew1 , I guess on this stage that's not only, and perhaps not mainly, about sharing with other users. That's about re-use for ourselves and not to repeat manually all these ORλ(), THUNK(), TIMER(), etc in each file. Like with OfficeScript - as soon as you create one and save with any file, it's available in any new file if you work with OneDrive. Not always good but requires no additional efforts.
Loading of lambdas collection into each new file practically costs nothing, that's just texts.
After some practice GitHub is easy enough and as any tool has pros and cons. Gist is limited solution, even with export. More complex one most probably won't work for the majority of Excel users.
As a sample AFE is a good compromise. I don't think that many people use all possibilities of Monaco editor which is behind the scene in AFE. We may start working with it right after the simple installation. Some stop on that, some dig more working on more complex tasks. Same with sharing, we need some mechanism which works from the scratch, without any dances around it. Basic functionality shall be in behind with ability to customise for more complex scenarios.