So this filter argument will reduce the repo size when cloning, but how will one reduce the repo size after a long stint of local commits of changing binary assets? Delete the repo and clone again?
At some point, what you're asking for may become a configuration option, likely tied to git gc. It's not there yet because it's all experimental and nobody is paying developers to work on the feature.
The old repo will still be pointed to whatever the LFS config was at that time. If that service is still up, it should continue to work.
In my case, with a 25GB repo, it was really detrimental to performance
To put it another way, regardless of what max size you give to --filter, you will end up with a complete git checkout, no missing files.