I agree. World doesn't need Bitcoin for buying a cup of coffee or for buying anything that can be bought with the credit cards maybe, but for remittances world needs Bitcoin badly. For sending quickly and much cheaper money half the way around the world, the word needs us for this as well. I gave you just two good, strong use cases.
So why adoption takes this long?
1. Bitcoin is still overly complicated, yes it is. To buy and secure your coins, you have to be very, very computer literate which most people are not.
2. People tend to change their habits very hard, especially financial habits. So this will take time, especially when we are dealing with money. People need to trust it first.
3. Directly or indirectly sabotage by our opponents. Yes, if banks came tomorrow and said to their customers, use Bitcoin, it will make our and your life much easier, of course they would boost our adoption almost instantly. Will banks ever do this openly? I don't think so. Instead they see us as a competition and they are building their own blockchains.
ad 1. Bitcoin is not complicated more that internet is. Internet was pain to use in its early years too, I remember my stressful moments when I wanted to find something and I couldn't, some services and apps changed many things.
I agree it isn't complicated more than Internet, but you have admitted that it was pain in the a** even for you to get used to it. Now add on the top of this pain in the a** also a fear about your finances, since you are messing with your finances with Bitcoin, no? Right away I can understand how some people can be reluctant to change something that works fairly well for them at the moment, their banks.
Example: My mother in law has been with the same bank for over 30 years. This bank is arrogant, highest fees, lowest interest rates, etc.. Many new players are in the market since. My wife and I have calculated that she would save or earn over 250 euros yearly if she would have switched banks. She refuses and doesn't want to think about it.