It also simplies the genesis block requirement for spin-offs: only the MerkleRoot is needed (along with the bitcoin blockhash for SCV). I think this should be the recommended manner in which a spin-off verifies a claim, even though it increases the blockchain size if a large number of claims are eventually made.
If a claim can reference an earlier claim you can avoid duplicating internal hashes. A valid proof need only reach a hash previously proven to have a path to the root.