You don't even need to make a transaction. Cryptocurrency based authentication mechanisms use the ledger as a "trust-less" root of trust. You know anything that

You don't even need to make a transaction. Cryptocurrency based authentication mechanisms use the ledger as a "trust-less" root of trust. You know anything that's been on the ledger long enough is valid. From their all you need to do is authenticate with the same PKI that corresponds to said wallet. A simplified example: You own an NFT and want to prove that you own it. You can produce some chunk of data (not a transaction) that includes a reference to the NFT (be it the UTxO, Tx, or some hash) and sign it with the same key that owns the NFT (or a derivative key depending on the design of the system). Since it's not a transaction it doesn't cost anything to produce and you can share it with the interested parties however you wish. In a sense you can think of it like GPG (and GPG based SSH keys) except instead of the web of trust being a federated set of servers and key cross signing, it's a decentralised ledger. It's not simpler but it can be easier because it largely comes out of the box set up. The PKI is already well established and you don't need to really spin up or configure anything complicated to use it. You just launch a wallet with the supported features and it "just works".