One problem with the market price for tethers is that it is actually very hard to sell them for USD. For example, Bitfinex does not allow USD withdrawals, only Bitcoin withdrawals.
Kraken offers a USDTUSD pair. How is that hard at all? https://blog.kraken.com/post/206/kraken-announces-support-fo...
Not true, bitfinex reenabled usd withdrawals in November.
Bittrex has a public pair between Tether and "True USD" [1], but their fiat USD market is not yet available to the public, and I don't know where we can find pricing data for the non-public market.
What is "very restrictive"? Cap on max amount for a given period?