Poorly thought out. Essentially blocks anything that is not ASCII, preventing anyone who does not use the Latin alphabet from speaking.
You can't configure the blocked characters, either. Also may have weird behavior for multi-char characters (since this plugin fits each into a char, this can lead to lossy casting for surrogate pairs).
Oddly allows $ and € but not ¥. Very inconsistent in characters and frankly, it doesn't serve much of a purpose at all (why block only 1 character?)
Use a better chat filter plugin out there.