because it is easy to use in onlline market. bitcoin acept all onlline merchant who was trading onlline.
the hell people still selling prices. it have lots of benifit for selling prices.
This has some truth to it. Not sure if it's what you meant, but if you are buying stuff online with Bitcoin and the price is down, you're spending more Bitcoin to buy the stuff and the merchant is probably cashing out. So purchasing with Bitcoin when the price is down contributes to the snowball effect too.