Right now rate limit for COPY command is:
COPYs per 5 minutes on any individual object in a Space
While it looks completely ok, some libraries like "carrierwave" for example, may hit this limit too easy. S3 has a limit of 3500 per second for COPY command.
Let me explain the need for this. Let's assume, we have a business logic object - product, with associated picture. And application user can copy this object with associated uploaded image. Such limit requires additional logic from developers, although saves storage space in the end.