Yes, it requires OTS and ethereum. OTS is free. Gas fees for delegations and revocations are tiny. A recent series of transactions creating a 3-key delegation chain came to about 518k gas. I think at current prices that may be less than $0.15. On-chain transactions are required only at the time of identity creation and key replacement, which is very rare. For people who don't hold ETH or don't know what it is, they can ask a sponsor to pay on their behalf. If you'd like to try it out, I'm happy to cover the tiny amount of ETH. You can go to

Inkan

Inkan web client

and click "Get a toy identity" to get a throwaway trial identity. On the last screen of the wizard, there's a link through which you can ask me to sponsor the transaction. For general concerns about using Ethereum, my initial response would be this👇