They’re not worth anything, never were but even less through the years with inflation.
If a store wants to sell something for 99 cent, they can either just take 1€ or 95 cent.
Maybe even 5 cent pieces? But that would be a bit radical.
I am a bit annoyed that easy ideas like this are never discussed in politics, or wherever. It would make our lives just a little bit easier, and having them achieves NOTHING.
I would guess that small denominations are used more frequently in cash transactions and are worn down much quicker. Therefore, it is probably reasonable to use the more durable coins for those instead of having to replace paper bills all the time in large quantities