Since checkpoint node already has some “memory based” caching built into it now, maybe it can use the library format to cache data to disk too. It could be a separate “mode” altogether, though I could see it being implemented with very few parameters hidden behind “Advanced settings” checkbox.
It could be a simple checkbox “Cache to disk”. It would save a temporary “tml” dump to the “temp” folder set in world machine preferences, deleted on session close.
It could expose a “path” field, potentially opening up a possibility for “persistent” library saving, in case someone wants a world machine project to retain this disk cache across multiple sessions (for example, during a material building and testing run).
I personally am a fan of “clutter free” separate graphs. But if it’s a built in feature inside checkpoints, I guess more people will find a use for libraries. The code should already be there, may be simple to wrangle this one.