Banks does steal money from us. How? Well they use money that we deposited from them and use it to loan it to other people with high interest, after that they will give us little interest per yer, in which inflation will take place that will lower the buying power of our money saved, Lets not be outsmarted by greedy banks lets find other ways to save money.
Inflation doesn't happen because banks lend out money, but to say that they steal our money because they pay less interest than they get themselves through lending this money out is laughable at least. It is their business, and if you don't like it, no one urges you to deposit your precious bucks in a bank in the first place. Entrepreneurs that take loans from a bank to start or run a business should earn even a higher interest off their enterprise, but this doesn't mean that they are stealing from you implicitly or from the bank directly.
Inflation will only happen to us because when putting our money in bank and if we think we will have a good income of the interest given that is not correct, the longer we put our money there the more the value depreciates, therefore putting your money in banks should not be considered as investment but just a mere savings.
Honestly, I don't see your point here. How can placing money in a bank increase inflation? Could you please explain what you mean. Banks don't need deposits to lend out money anyway, since money can be created "out of thin air" by the banks. Strictly speaking, it is the Central bank behind private banks that does just that. The deposits of regular people cannot possibly boost up inflation. You, and those who think along the same lines as you, seem to be confusing something.
I do not believe that you should have all funds of your portfolio in btcs, and nothing in cash. Because, as you probably know, you still can't buy everything using cryptos in these days. You still need paper money, to use in your daily life.
If you are using a Bitcoin payment card which is linked to your Bitcoin wallet, you can basically buy everything using bitcoins nowadays just like you buy things with a typical bank card.
Here's the comparison of the six major Bitcoin payment cards for anyone interested in the question.