651 USD for a Bitcoin sounds pretty nice ar current levels buy why not go back a few years more. Imagine buying a coin for 1 Usd, you would have already made a nice profit of 651 times your initial investment. Unfortunately these backward analysis of potential investments are not good for us. With almost any stock we could find the best timing to buy and to sell. It's better to look for new opportunities for the future than feel bad about missed out trades.
Feel a wee bit sorry for all those poor souls who sold their Bitcoin holdings after the initial huge price increases from a couple of months ago to now because they cashed out for fiat and can no longer buy them at the same price!