My take on it is blockchain will revolutionise the payments industry and if you could invest in that then I'd be all for it. The crypto-currencies themselves I'm not so sure. Seems to be a new one every week and they can't all last. Some people will make huge amounts of money on them and some people will lose their bollox.
We are at the start/middle of a cryptocurrency bubble. The amount of people who ask me about them or tell me they've invested in them (and when I ask them why) haven't a clue other than they heard you can make good money in them is unbelievable. See tech stocks in a previous generation.
When you start buying something in the belief that it's value will rise for no intrinsic reason, other than the value has risen previously, you know you are in trouble. See previous in; Tulips, South Sea Shares, Railway shares, Internet shares, Irish property etc. etc. etc.
Similar to internet stocks, people could see the internet was obviously going to be a game changer but you couldn't invest in "The Internet" so you had to buy stocks. Similarly blockchain will be a game changer but you can't invest in blockchain as such. Maybe a handful of crypto-currencies will survive and thrive, but we'll see.
Anyway all that said if you want to have a punt with a bit of money you can afford to lose go mad, be good craic anyway. Just remember to get out at the top