No no no, I'm not implying you should share your private keys with me. Unless of course if you feel an irresistible urge to part with your crypto-currencies, I shall gladly stand at the receiving end of that deal :-)
No, we don't share our private keys
We guard them well because we know that this key gives access to our money; losing it is the same as losing your wallet, safe and bank account. So we write them down as a "paper wallet" and hide it where no one can find it, we store them on encrypted USB sticks or on hardware-wallets and never share them with anybody. We never leave our coins on an exchange too long because *they* own all private keys your money is stored on. You have no control and the Exchange is a centralized weak link in the chain we try to lock our coins with; they are the ultimate honeypot for hackers and are often compromised because of that very reason.
Still I want you to share your private keys
Why? Because nobody can see the future and we are all mortal beings. Private keys that are lost, are lost forever. Bitcoins on a private key that is lost, are gone forever and for everybody including your loved ones, your family. That is why I urge you to keep guarding those keys from everybody, except the person or persons you trust and love most.
From a 2017 Fortune.com article:
A young man died suddenly in Colorado this year, leaving his family the burden of sorting out his estate. Little did they know their loved one had been investing in Bitcoin, the digital currency that cost as little as $13 in 2013 and recently climbed as high as $5,000.
The grieving family stood to inherit a small fortune—that is, if they could only find and access the cryptocurrency.
I have a girlfriend, a son, we bought a house and am the only person in the family with the crypto-virus. I would want my girlfriend and son to have access to whatever crypto-currencies I have in case something awful would happen to me. I'm even teaching them about it now so they also have an idea of what to do with those private keys and how they can be converted to the fake money (fiat) they will need to pay for the funeral...
source: Ann Larie Valentine (flickr.com)
Bah, getting a bit morbid there. Sorry for that. But I still would like you all to heed this little piece of advice. A good portion of the allotted 21 million bitcoins have been lost forever already. Many families have already discovered that a lost member was a crypto-holder while still alive and have no way to access the money. So share those keys, put them in your last will and testament if it comes to that; just make sure to also include a written manual on how to get the fiat money ;-)
On a side note,
It's not certain how many Bitcoins have been lost until now. A key (no pun intended) difference between Bitcoin and Fiat money is the limited supply of 21 million coins, and this is also one of the main reasons why we predict its price going to astronomical heights eventually. There are already an estimated 4 Million Bitcoins lost forever; maybe Bitcoin's price will go even higher than we already expect :-)