U need to know that some time ago a big amount of BTCs were used for buying illegal things.

Alphabay is the biggest darknetmarket and there are millions floating around everyday.
I made huge profit years ago just reading that a big alphabay dealer is going to cashout btc.
so that maret has in fact a big influence in cryptocurrencies.
Alphabay even recommends to dealers now accepting zcash because of the fast transaction ... and therefore not a big risk of losing btc.

I really think that zcashwill pump soon because the dealers are pissed off of monero now.