Invest in tether is not a good way for profit and you can not trade tether with real dollars. Anyway, if it is tradable, the trading fee will kill traders who want to trade tether with dollars.
OP didn't mention anything about making profit with tether. Converting your crypto to tether is one strategy to secure your profits when the prices starts heading down like where we are now.
I don't hold any tether though i'm fine with holding my coins and it's stressful when you have to watch the price every time just to move your coins to an exchange and back.