I will checkout Boardwalk Cash.

About Tether, and all stable coins that are tied to an asset, especially US Dollars they can all freeze your account, and maybe even take your funds away. This has happened before with USDT, and the rest are not an exception.

That said DAI, an Ethereum based stablecoin is more reliable, and can not be arbitrarily frozen or seized. We need something like DAI but for BTC.