Where does the value of money come from? - Question about the monetary system

If I have 1€ and everyone else has 1 cent, I am rich. If everyone suddenly has €1, no one is rich anymore even though nothing has changed in my number. Doesn't that mean that in the end it's all about ratio and not the absolute amount? And if that's true, don't you lose value as soon as others get more, even if you stay the same? What then is the idea behind increasing the minimum wage? Does this actually solve a problem or does it just shift the relationships? Is that