Because USDT is seeing a sudden growth, there has been several regulatory scrutiny from United States. A report came out from Forbes last 2 months that Tether has been saving more than half of than half it USDT reserve in the United States banks but a recent report claim they are longer in the US. It is good that it reserve is no longer in the US because the US authorities may want to freeze the reserve one day. Now that the Tether's reserve is no longer in the US, it means that it reserve can not be easily ease but the is potential that tether may still have connections to the United States banks which impact the USDT if some weird happen.
Another good reason why we are seeing huge growth of USDT, is the demand for US from countries that are not having good relation with the United States. There are a time that the US dollar was the currency of choice for the Chinese elite to move money in and out of the mainland. If it is true that that is still the same thing that is still happening, that means that countries like Chinese and Russia will make sure USDT survive. It is important you know that there are more things to cryptocurrency and macro economy that draw people's attention.