Yep we're need Bitcoin, but don't ignore the fact we still need fiat too because not all merchants will accept Bitcoin... even more if you live in countries where Bitcoin still in grey area, you won't see any merchants will accept Bitcoin.
Average Joe will think fiat is more safer than Bitcoin in terms physically and wouldn't loss since most bank offer insurance if the bank bankrupt, unlike Bitcoin it's non physical and will loss if the exchanges got hacked or compromised. This is why people should educate yourself to understand Bitcoin is and using exchanges only to trade, not to hold.
It is important to understand that not all countries legalize Bitcoin as a means of payment,
so Fiat is still very much needed in every country,
Hacking is indeed still a scourge or anxiety for those of us who use crypto, so we need to be careful and improve the security of our wallets.