The standard advice is that normal people should never try to beat the market by picking any single investment, but rather put their money in index funds. The best publicly available information is already considered to be reflected in the current prices: if you recommend in buying a particular investment, that implies that you have knowledge that the best traders currently on the market do not have. As a friend commented:

The only rational reasons to hold a highly volatile, speculative investment are either if you have a huge risk preference (and with bitcoin we're talking about crack users) or if it's a really small share of your investments, of which the majority are really low-risk investments.

So if you think that people should be buying Bitcoins, it's up to you to explain why the standard wisdom on investment is wrong in this case.

(For what it's worth, personally I do own Bitcoins, but I view it as a form of geek gambling, not investment. It's fun watching your coins lose 60% in value and go up 40% from that, all within a matter of a few days.)