json rpc – What is the purpose of the “category” Bitcoin Core RPC API field/property?

When using the Bitcoin Core RPC API to list the transactions, there is a “category” property, which can apparently be either “send” or “receive”. Then there’s the “amount” field, which is like 0.05 or -0.05.

Don’t we know whether it’s a “send” or “receive” merely based on the amount? If it’s positive, it must be a “receive”, and if negative, it must be a “send”… no?

Is there any reason I should be storing whether it was a “receive” or “send”, since I can (apparently) just look at the amount to see if the number is negative or positive?