I recently noticed it too. In my mind Tether's market cap was 1-2bn and I was in a mini-shock when I saw it x10.
Imagine what will happens with the whole crypto ecosystem if Bitfinex screws the stuff.
LOL. $1 billion was the market cap three years ago, in 2017. After that there was a steep increase. But most of the increase has occurred in 2020, when the market cap went from $4 billion to $20 billion. Worryingly, this means that at least some of the cryptocurrency users are holding their wealth in Tether, rather than using it solely for trading. It is just like holding your coins in exchange wallets.