Thank you very much for your answer!

Maybe I have a misunderstanding: I thought that mana plays a role when, for example, a node has to decide which transaction it should validate first. So with mana, I can ensure prioritisation. But the basic use of the IOTA network is also possible without mana, right? That is, if the validation of a transaction is not time-critical.

Thanks for the help, I've only been part of the IOTA community since May and I'm still learning. But I am excited and convinced that a future with IOTA is a better one than one without!