Well that's the hole point on buying tether, since it's suppose to act as a a virtual dollar. Of course that since it's not an actual dollar, it can lose value or even be shutdown, since it's centralized. I think that if you can have access to an exchange that actually pairs bitcoin to fiat, you should opt for this instead, as you would be much safer this way. It's still an exchange, and we are seeing some banks temporary closing exchanges accounts, but I would still prefer it to tether. There are also some coins that are outperforming bitcoin right now, so you could also try to accumulate more bitcoin by trading those pairs.