In addition to that, the fact the it virtual also contributes to the reason why it can't completely replace or substitute the traditional fiat currency. not everyone likes the idea of having their money in a virtual form, especially some old folks who are not quite familiar with the dynamics of Bitcoin. most of them are more comfortable having their money in a physical form or stored in the bank where they wouldn't have to do much to get it back in physical form.
Our world is becoming more and more digital, many older people used to not know how to use smartphones, online banking but that is slowly changing. Maybe not too soon, but sooner or later, I believe a cashless world is inevitable. But even then, bitcoin still cannot replace fiat because they are completely different.
Simply put, fiat is an essential tool for governments to manage and regulate the economy and manage people. So if there is something that can replace fiat it will be created by the government. They will never let something they cannot control dominate, it is like their power is lost.