Yes and the fact is we cannot use bitcoin physically at a moment and that is the reason fiat will always be in demand and even in future there will be many people who will prefer to use fiat.
As of today fiat are still important as the people doesn't even know what is in the trend of technology. But once the government is going to implement the use of bitcoin.
For sure bitcoin will replace the use of fiat.
Do you really believe that Government will standby bitcoin ever in future? I don't think that is ever possible as fiat holds maximum users and they find it using very easy and convenient.
A day wil come that governments will also start to support bitcoin and will implement its use in their countries,but still fiat will renmain where it is, as more people feel convenient to use their local currency for their local markets etc.