Inflation is the rate at which goods and services become more expensive. They either need to become more expensive or generally more available in order to keep up with a growing demand. The demand grows with worlds population, or development of rather poor countries striving for prosperity.

Also inflation of a couple percent is a wanted phenomenon which can be directly controlled in a wide area by THE banks like the Fed or the ECB. How? Inflation is literally the price of money to own. If you have a lot and keep it rather putting it back into the market, by spending or investing, e.g. firing up ecomonical growth, it will cost you buying power in the future.

So why keep a Million in cash that next year will only buy me what today is worth 960,000 if I can aswell lend it to a company that will use my money to produce something, contribute to the economy and grow its own value, which will pay me back 1,040,000 next year?

Without inflation no one would invest. Riches stay rich without even having assets in the rest of the world.