see this thread on examples for replacing characters in filenames:
/t/13835/1
You use the function only for one specific format string either in the Convert>Tag-Filename function or in an action of the type ""format value" for _FILENAME.
There is no sideeffect unless you call the same function with the same format string again.
Edit: just thought of it: band names like AC/DC, Colourbox M/A/R/R/S, De/Vision will look strange in the players that take the / as separator between artists.