How to deal with taxes?

I mean one of main reasons that most people are buying bitcoin is to keep it as their money which is jot going to getvalue decrease like dollar etc...

But the problem is, if we are having it as a digital currency and it is a money rather a securities or commodities, so why we should pay taxes for it? And how do you deal with tax? Because it doesnt fair to me to pay tax for my own money, what did I do? I just changed my eurs to btc and keep hodl, and sometime buy stuff with, why should we pay tax for the money?

What is your suggestion? In general and in germany what is the legal solution