Tether is fascinating for sure. Tether is currently the heart of the cryptocurrency space, it provides liquidity and risk management (via a stable coin) "on-chain" without relying in a fiat currency. Tether has more daily volume than Bitcoin. Tether is accepted in mosts places and there is local liquidity available. Tether could fail surely, if it failed then all crypto will go deep down. And it is important to note that the people behind Tether are deep incumbents too, not just random project.

USDC which is more scrutinized is 1/10 of the Tether volume. BUSD 1/4 (not bad!) [1]

[1] https://coinmarketcap.com/ (sort by volume)