that's because they really, really don't understand it: all their experience is based on fiat currencies. and as crypto-currencies go up in value, fiat currencies correspondingly and naturally *go down*. this is something that everyone is forgetting, that, ultimately, the value of fiat currencies is going to be quite literally worthless.
a good book to read which outlines this in an easy to read fashion is senator ron paul's book, "End the Fed".
I am afraid `going up` is problem at the moment.
Currently you cant sell crypto to USD, there is lack of liquidity. Most probably there are some top holders of i.e. Bitocin and try to sell it to fiat as much as they can in this moment. it is classical ponzi scheme where few will get rich and minor investors will pay for it.
You cant purchase things. For example go to shop and buy a car. Price fluctuate 10,20,30% daily, so even if you are benevolent toward idea you cant really hold goods for 6 months and be sure that you will at the end make some margin. Remember, trade (business) is not about speculation but making margins in predictable way. With fiat you can go in restaurant and buy cup of coffee. With cryptos not. There is no economy behind it, just good idea and hype.
I have seen two projects based on cryptos in last two years, they are not coin speculation but real ideas that society could benefit,that are difficult to implement because lack of legislative, government want taxes, stakeholders resist it etc. Unless you see some real business and/or services based on blockchain there will be no real value of crypto-currencies.
Yes, ti is good idea, but what is going on right now is not good at all and if balloon burst it could do more harm then good.