Why is it cheaper to replace JD.COM's household appliances? COM？

Reasons for Cheap Household Appliances Trade-in in JD.COM;

Offline entities are difficult to do, combined with online sales. I can't help thinking that this secret will eventually become "not a secret". What will happen to offline businesses like Suning Appliance, Gome Appliance and JD.COM Store? The friend added: Not all brands and all goods can be delivered at low prices, and prices often change every day.