I wonder who would use this kind of node. Sending transactions would typically require an eth_estimateGas execution, which uses a call under the hood.
I guess people who are interested in watching for event logs on chain, but not accessing arbitrary state? Or maybe application-specific nodes, which are some kind of stateless hybrid. They might download all the storage needed for a particular application or two, but run stateless on the rest. That seems to be supported by this model. Do any other use cases come to mind?