It depends on your point of view. The Biddle Move represents a way of stealing and/or switching cards which are on top of the deck for some of the cards in your hand. This had been done before, of course, by Hofzinser in the form of single and multiple Top Changes, as well as in the form of switching portions of a packet (one card of two, for example). But these techniques are difficult, and doing it with a Biddle Move is simple.
With Dai Vernon's extensive use (and publication) of the Double Lift and Double Undercut, and Elmer Biddle's publication of his sleight, by 1950 all the elements were in place that allowed anyone to do with minimum practice many tricks that previously required Passes, Top Changes, and Palms. This was the beginning of the modern era of card magic.
The last book of the earlier era is The Card Magic of LePaul (c.1947 or so). The first book of the new era is Bill Simon's Effective Card Magic.
Without these innovations by Vernon and Biddle, virtually none of you reading this would be doing card tricks today.