Bittrex will allow you to deposit FIAT to them.
Provided you're willing to send more than 100K USD. They will exchange to USDT on 1:1 basis.
Yeah pretty much. They're basically accepting fiat through this USDT proxy probably because of regulatory concerns, they do not want to become an actual fiat currency exchange and rather just stick to whatever they are doing now.
For anyone interested the change was made a while back in August and can be viewed here:
https://support.bittrex.com/hc/en-us/articles/115001293992-Purchase-USDT-via-Wire-TransferIt's not for everyone though with the $100k minimum deposit, and even for the whales i doubt they will choose bittrex honestly. There's a lot of exchanges with better features and more volume, as well as better support that support fiat direct.