Take your pick. If it's lengthy then it's been written by someone else somewhere.

Maybe the short ones have been too. Can't be arsed to check.

There is no way to answer this 100% . It all depends on what is going on with said coin. Altcoins USD or EUR price is determined from the BTC price of the coin. When investing in altcoins that are purchasable via bitcoin, you want to take a look at the btc price of that coin.. That is going to give you more information vs. checking the USD or EUR price.

Ultimately, cash may in fact disappear. But it’s mostly a question of where and when. While it may disappear in some countries, it might remain in others. And if it ultimately happens in 50 or 100 or more years, it won’t matter much to anyone who’s alive today.