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.
I agree with this because at least when people still use fiat and if something bad happens, they can ask the government to help them fix the problem.
But when something bad happens to bitcoin, they can not ask anyone except themselves why they put their money in bitcoin.
Yes, not many local merchants accept bitcoin but fortunately, we can use bitcoin and convert it into fiat so we can still buy something using that fiat.
Those people will still use fiat because there is a guarantee from their government but if they can open their minds and know bitcoin, they should invest in bitcoin, just in case, bitcoin can help them when they need money in the future.