This is very inefficient
Takes tick time
Force system to flush data to disk.
Is wearing SSD drives.
Only Multimine does this

And here it does this with a 200k config every few seconds.

What you are probably experiencing is Multi Mine writing each block and item to the config banlist as they are encountered (however, each only once ...). After a block or item was loaded from the config (and saved if not previously in there) once, they are cached in memory.

I don't recall why i chose this approach and with stupidly large modpacks and mountains of mod objects it might be an issue. That being said, if a 200k config file being written over and over will take a couple hundred years to kill your SSD. Complain to me then.

Well i vaguely remember people complaining about not being able to add mod items to the banlists correctly, that may have been the origin

just ok

Please change the implementation it causes a lot of TPS lag... see this issue: #291