Biggest gadjet and tech chains still haven't hopped on the Bitcoin bandwagon. Dealextreme, Gearbest, Banggood... etc. It's not only a question for DX...
Why? They're probably too busy with their current profit
Speaking more seriously, they have a load of work updating their current sites as it is, and they probably don't want to "waste" time and money adopting Bitcoin... For now. They haven't realized how Bitcoin can improve their profits