At this day in age, cash is ABSOLUTELY not better than bitcoin from an investment standpoint, as cash goes literally nowhere. But from a convenience standpoint, cash will almost always be king because it is an accepted form of currency literally almost anywhere. The only place that I have seen recently that actually won't accept cash is a few high end furniture stores. I have no idea why they don't accept cash, but I can confirm that they don't accept it at a few, because I have personally tried.
We can't find the value if we compare two thing with different purpose, bitcoin is an investment while cash is not so in that view we can '
see bitcoin which is more useful. Bitcoin was not primarily created for investment, in fact it's a good tool for payment online which cash can do.
If we will look at the bigger picture, cash is better since it is widely used compared to bitcoin and it is recognize as a legal currency.