ha ha, so funny, yeh, sliding cards is a European way used by croupiers mostly. I comes about from increased game security by sliding rather as pitching as the deck is always in contact with the table in plain view, there are many unlicensed poker dealers who pitch and the american influence does increase the use of pitching with most untrained dealers pitching. On a poor surface, or limited size I will pitch and toss, but on a full size table I always slide, it's faster easier and leaves less scope for things to go wrong, or as Brian says, pitching is rather uncivilized by comparison.
Stuart