Quote from: blambaba on January 20, 2018, 03:32:22 PM

However, no one actually uses Bitcoin for sale.

Fortunately you're wrong and lot of people use bitcoin for buying stuff.

Quote from: blambaba on January 20, 2018, 03:32:22 PM

Who will use Bitcoin to pay when only 10 minutes later, Bitcoin prices may soar 500 dollars? And which seller will receive Bitcoin from customers when the price of this kind of money can drop $ 500 only 10 minutes later?

The opposite might also happen.
If you get a good deal in BTC what is stopping you from using the $ you would have spent to buy back the BTC. Nothing!!!

Again, most sellers don't take bitcoin and store them in wallets.
When your coins reach bitpay they are exchanged and the seller gets xx$ in his account. No matter what the value of the coins is.

And back to your claim that nobody uses bitcoin, why do we have 300k transactions a day and 150k in the mempool?