nobody wants to buy a cup of coffee with bitcoin, or maybe there are some people who wish they could and if you let them, they will.
but everyone wants to be able to use bitcoin as a currency. for example i want to be able to purchace a game online (worth from $5 to $50) or be able to pay for my subscription etc. and a lot more.
Exactly. The key distinction here is that Bitcoin is a
digital currency, and is by far best used and most convenient for
digital items. People like convenient payments for small everyday transactions, and that's why we have situations where you either pay with cash, which is instant, or by credit card, which for most conventional purposes is instant. For the really small transactions, the $1-10 transactions which we go through every day, it's also much, much cheaper (in the case of Visa cards, about 0.2%).
Bitcoin is best used for large digital transactions as fees are based on the byte which tend to result in it being a lot cheaper for large transactions, and best suited to digital transactions as it is very convenient when dealing with others online, especially people you don't trust with personal information.