eth_estimateGas and block parameter

Does anyone have use-case for the block parameter in eth_estimateGas? I just stumbled over an ancient (2016) bug and not sure yet if it should be changed in the documentation/spec or in geth. But I think we should do something about it to remove this stumbling block.

Also as @karalabe just pointed out - the documentation is also inconsistent in this regard - this section does not mention estimateGas:

use-case is found - but in the end the rpc-spec should still be changed to allow also a blockhash and not only a number: