In one function, I was forced to declare a variable with the memory type storage (since there is mapping inside the struct). Is it much more expensive than memory? And how justified is it if I will use this local variable only for reading? I compared the cost of a call in Remix with the memory type and the storage type.
P.S A call with storage memory turned out to be even slightly cheaper. This is because there is no new copy being created for memory, right?