Why not. Sell your coin to tether to weather short term price dips and transfer between exchanges.... If tether is unsustainable long term, who cares?
I don't know what's going on with Tethers, honestly, it's not something I've followed very closely; so this may not be a problem at all (and if it's not, I would assume the people involved would be eager to get an audit done and results published so the money train can keep rolling). I'm just saying that unless you believe strongly that Tethers are backed 1:1 by USD, it would be irrational to hold Tethers, even for a short time.
I found it worrying that when the guy they interviewed tried to move his Tethers to another exchange, he couldn't find enough takers (and Bitfinex wouldn't let him exchange for dollars either). So, the argument that Tethers trading at roughly $1USD across exchanges is "proof" that Tethers are sound is shaky, at best. If you can't sell more than a handful of Tethers without crashing the market for Tethers, it's not actually the market setting the price. Something else is going on...something that would be illegal in a regulated market.
I get that I guess it's not easy for someone in a major city or whatever.
Cryptocurrency markets are dominated by highly rational traders with deep pockets.
Just because a bunch of newbies are buying 0.002 BTC on Coinbase doesn't change that fact.
Highly rational traders with deep pockets do care. Getting hand-wavy talking about "irrational markets" doesn't adequately explain why Tethers trade at parity to USD.