-An average online card based shopping has a 4-8% comission on it by start, with bitcoin its about 2-3 cents (0.0001-0.0002 BTC)
-An average online card based shopping takes 2-4 days, bitcoin takes 10 minutes
-Wire transfer shopping is even worse, up to 5% comission +25€, so if you want to buy a 0.5€ pencil online, you pay like 30€ for it.
-Card based shopping is full with frauds, and if you have like 2000€ on your bank account, the thief can easily rob it, and then it will take you 6-12 months of police and other legal procedures to recover the money (if it can be recovered).
-With bitcoin you can just put 0.5BTC on your "shopping address" and keep your other 100 BTC on a safe cold storage wallet, so even if somebody steals your wallet he gets away with less (more diversification & risk control with bitcoin)
-Bitcoin is available for minors too, in some countries 16 year old is already eligible for work, yet he cannot have his own bank account without parent agreement which is nonsense. If a 16 year old guy works online to get some extra cash in bitcoin, and he spends it wherever he wants, thats his money and the government should not restrict that at all.
-Banks are not the safest place to store money (see Cyprus govenrment confiscation, Pension looting and other governmental thefts that occur nowadays), your bitcoins on the otherhands are invulnerable to government theft.
-Bitcoin doesnt have global restrictions, open to P2P trading, I can sell p2p anything, otherwise if i would have bought it from a central store you need to pay VAT tax on it, p2p trading is not taxed, yet, and it's more efficient.
-Bitcoin doesn't discriminate racially or politically or religiously between users (see EU and USA embargoes on "enemy" countries)
-Bitcoin is free market trading, its monetary freedom, and capped supply, while fiat money is an inflated toilet paper money.
and many more...
An average guy can easily understand this, dont need a 160 IQ to understand that the governmental-monetary system is highly flawed.
Yes, we all know these. But still, average Joe don't care, fiat money already become their standard of value since they were born, and as long as it works, they don't have enough motivation to switch to another totally unfamiliar system
True, bitcoin transaction fee is almost zero, but to exchange value in and out of bitcoin is not free, usually it costs much more than the 3-5% fee of credit cards, and it does not provide consumer protection like reversing the payment. So no clear advantage from payment point of view
The advantage is at long term storage and international remittance, which also requires user to have outstanding IT/Financial experiences in order to handle bitcoin security and exchange related risk
Fiat has established trust, and people are short sighted. Most importantly, because their income all comes in the form of fiat, they even fight to protect its value. Even banks printed money for future 100 years and bought everything valuable in the country, average people just don't care, as long as the price in supermarket and gas station does not rise. Of course they will gradually learn the truth from internet, but by the time they start to react, banks already bought the whole planet