For a start its on the ON INPUT not a ON TEXT so it only checks the INI file once for every time you enter a line. and you can always just NOT read the INI, and when someone changes the command character, then your script doesnt work, wouldnt that be good.
So as to slow? No its not, and no it doesnt put any great file access stresses on anyway, thats what caching is all about.
As to a slow down in general, since it never trips untell your completed a line of text, and the machines idled around 90% of the time while your typing, i dout its much of a system drag.
