[PKop]

>sell for FIAT

It's interesting to think about how in the short term at least, people would sell USDT for anything, particularly BTC, ETH and other stable coins like USDT or DAI in this scenario, so I would expect a price spike in BTC if there was some critical event where USDT collapsed.

I guess it would reflect a false value of real liquidity in the whole crypto market so would have to depress BTC price for a time after the dust settles.

[nikanj]

Price spike as measured in USD or price spike as measured in USDT?

[PKop]

Dollars simply because it is an increase in demand. Of course, the relative dollar increase would be less than the USDT denominated increase. If USDT is pennies on the dollar, but these fractional dollars are bidding for BTC, BTC will go up in dollars.