in PoW blockchain method the client has a time limit for receiving hashing answers from the blockchain network, so it can assure that it is connected to a blockchain with an International-scale hashing power. It is safer than log transparency.
Out of curiosity were you aware of this safety feature of PoW blockchain’s method?
About bitcoin network fees, layer 2 should be used. Layer 2 security depends on the main blockchain. I think BlockStack has done the same and it is free to use.