Again, what makes you think so?
With my credit card I can buy a coffee or a TV and I expect it to work the same. Why would it be different with Bitcoin?
Why is keeping track of my daily expenses not needed? How will they be validated otherwise?
Your credit card don't work on the same way than Bitcoin. You just can't store every record of the world on all nodes of a distributed network.
it's just too big to fit.
Also, if we have the unbanked transaction, Bitcoin would have to handle more transaction than bank centralized systems.
that just make no sense, you have payment systems that are more convenient to use than bitcoin, that are insured, fast. (and new ones that will be developed)
It's not in payment system that bitcoin is the best player.
Bitcoin is the best player in managing property of coins trusting no one, under no autority.
So each time you can afford to trust something, you don't need Bitcoin. and each time you put things that don't really need to be included in the blockchain, you weaken it.