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1. If we are loading the prior result in a stateless operation, there will be a significant performance impact. NOTE: However, this can be subject to change: if we can generate some integer id (such id generation would likely fall on the user for implementation) which can reflect changes in the processed result, then we might be able to extend dropping no-ops to stateless operations as well. This is still an alternative worth considering.
2. The other reason is that if we are loading a prior result in its entirety for a stateless operation, we are essentially replicating some functions of a stateful operator into a stateless one. After all, a stateful stateless operator was never intended to load a prior result (only a stateful operator should do such a thing). That means there would be some redundancy between stateful and stateless operators. However, this discrepancy can result in much confusion from users.

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