What is the purpose of __ExternalActors__ folder?

[Attano]

I may be missing something, but if the intent was to separate files that are mandatory for the system core's work from non-essential ones(e.g. those used in demonstration maps etc.), then what's the point of creating 'sublevels of importance'? I mean, I can safely delete both ExternalActors and ALSExtras. So why not just have keep them as one folder?

Also, why do the files inside ExternalActors have seemingly random generated names?

[Sixze]

This is the "One File Per Actor" feature. Actors from Playground level are now stored in this folder instead of a monolithic .umap file. Unreal automatically manages this folder so I can't move it or rename files inside.