The concept of bitcoins and any non native currency is fundamentally broken. There is no cap to how high a bitcoin can be worth.
It acts as a 'digital asset' and not as native currency.
Non native currencies are economically bad. This is because it is easier to buy a bitcoin than earn it or spend it.
Bitcoin is nothing but a geek's/technology enthusiast/new-age toy. It will remain that way because it was allowed to reach
insane values. Once the bitcoin crossed 5USD, it was doomed.
There are no smaller pieces of bitcoins. This means it it became mainstream, its value is going to diminish to allow smaller purchases.
For a currency to work, it needs to be able to take over. You can't go to a supermarket and buy half a KG of cheese with bitcoins. You can however buy it with your credit card or cash. People can argue that it is intended to internet purchases. That still doesn't help because internet purchases are often items worth less than a bitcoin. Therefore it is only useful in certain situations such as a
university in Cyprus that allows tuition to be paid in bitcoins. Banks discourage currencies that are only useful under certain cases. They only encourage currencies that are useful in all cases and more importantly, only currencies that can be safely invested.
Again, for the sake of the argument let us assume that sometime in the future, the whole world switched to bitcoins instead of their native currencies. We all walk around with some digital wallet devices that hold our bitcoins. What is going to happen if this change occurred? We can compare this to the problem we had in Lebanon over 20 years ago with the dollar. The dollar which was once 3 Lebanese pounds suddenly became 2500LL in 1992 (down to ~1500LL now). The US dollar will suffer the same fate to bitcoins that the Lebanese pound suffered to the dollar. Everyone lost the value of their investments when they bought dollars.
The bitcoin will end up having the same economic value of the current dollar. A bitcoin will buy you two Pepsi cans.
Therefore, to keep its value, a bitcoin needs to remain a 'virtual asset' that can be traded for only certain online items.