It's basically like the older PGP/GPG technology compared to the more prevalent and high-electricity-consumption solution in the mining of computational complexity.

So basically I believe the dip in BTC and cryptocurrencies in general is because centralized investment went out having been tied directly to electricity prices, amplified by speculation. I'd also think to look into, as a possible cause of previous market fluxes in cryptocurrency, the crackdown on Silk Road, where BTC value was tied in some part to drug market prices.