I'm not talking about theoreticals, or even FFXIV specifically here.
I'm simply asking about whether or not a value changed, potentially many times per second, with every hit / tick [Chain bonus] could possibly work in an MMO.

This is a technical question. If you nothing of the limitations of servers, please don't bother answering. If you have even a good guess, with some evidence as to why it would or wouldn't work, I'd appreciate it.