Not everyone wants to be responsible for their money. Fiat actually has built in protection for users because of its reversibility, however the drawbacks for having that ability is much more of a con, than it's a pro for me. So, basically banks will always exist for these types of people.
I'll give a stereotypical example, though this isn't, and shouldn't be taken as representative of the population. Imagine, a person of the older generation who isn't very technical when it comes to computers, in fact they struggle to use modern computers, and these types of people are unlikely to understand Bitcoin. Bitcoin while the usability, as well as the accessibility has definitely improved over the years, since includes technical terms. This type of person I'm trying to give an example of isn't likely to understand mining, and isn't likely going to understand security on digital devices. Thus, a third party which manages their money will be beneficial to them, since it has added in fraud protection, security, as well as ease of use. This isn't going to happen with Bitcoin since the key element to it is you have complete control of your money, which results in you being completely responsible for your money.
Bitcoin, despite the wallet software being much more user friendly, is still difficult to use. For example, checking an address to make sure its accurate, checking fees so you aren't grossly overpaying, since most wallet software overestimate, and assuring you follow security protocols so you don't risk your funds, this isn't something which is easy to do for the typical non technical user.
Unless, Bitcoin becomes much more user friendly, and provides a
idiot proof system of sending, and receiving Bitcoin its unlikely to suit everyone. Although, I believe banks will always have a place in the world, they'll only be used by certain people with certain goals, the vast majority will likely see the benefit to having complete control over their wealth. However, what's clear is banks will need to adapt to this, they'll definitely be losing business in the future, and they'll likely need to adapt the way they work to fit this certain demographic that will require their services.
What is the nature of bitcoin? It is untraceable. Why do people use bitcoin? To stay anonymous If the only thing in crypto is to be anonymous, If these are the only reasons for using bitcoin, keep your portfolio private and use complete financial freedom.
Not really accurate. Bitcoin certainly isn't untraceable, in fact Bitcoin is more traceable than cash. The public ledger makes it possible to see every transaction ever made with Bitcoin. I think what your getting confused about is; Bitcoin is pseudonymous, and therefore it isn't obvious who made that transaction i.e the identity of that person. So, while there are more privacy oriented cryptocurrencies than Bitcoin, cash is fairly good for anonymity itself. This isn't the major selling point to Bitcoin, far from it.