Why? Because I wanted something that works predictably, and is guaranteed to be performant. No random inserters removing modules when you don't expect it, no periodic checks via a script. Put this next to any assembler, drill or silo and it will be able to proxy the module inventory for your inserters.

Note: when pasting in a large blueprint containing a lot of these machines, settings may not be copied properly. Paste the blueprint over one more time to fix it.