Trust me, hes not. Hes more than likely just trying to get you to buy something that costs more that will keep you coming back for more.
Impaction is a very slow process, calci sand/reptisand turns literally into cement when a beardie eats it, one missed cricket bite and lead to death on any particle substrate. It will also dye your beardie the color of the sand which is why some beardies at pet stores are red or blue. Keep it simple and either use paper towels or ceramic tiles