This is the opposite of true: I made hundreds of dollars on MTGO last year just by buying staples and selling them when they spiked (and not even on purpose, it just worked out that way with Jace, Snaps, etc.) The concept that MTGO objects are literally worthless hasn't made a lick of sense in a long time given you can, in fact, sell them for real money and further to the point, you can liquidate them dramatically faster than you can real cards.
If you're saying that lots of the digital cards are worth way less than their paper counterparts and don't sell for anything, it also means they don't cost very much to buy.