you can deposit or withdraw ETH or W(rapped)BTC via smart contract and all you ever pay are the Ethereum fees for calling the smart contract, which is usually around 2 USD. A lot of advantages with this solution:
...
- No one can steal or confiscate these funds
Except for the BTC <-> WBTC bridge operators.
Have you ever considered building a similar platform on Bitcoin itself?
It seems like the technology is already there - RGB is gaining traction, and Rootstock is still around too.