USDT has enourmous value which means some of the prices arent sustainable, because of upcoming btc Chickago event. I personally think that this btc price range wont be sustainable even if wales and sharks are flashing market trading on high levels betweenthemselves and creating prices which enables them to reset altcoins even if not making money on btc.
Those alt prices we saw and all those enourmous uptrends which will be corrected to previous prices and they will probably drop even more then previous values before this uptrends. Also possible scenario is that wales n sharks are buyin' alts, artificialy increacing prices and trading, making real money there, while trying to slow btc downtrend which is inevadable. I would not suggest buying anything else on these price levels but it will dump as prices drop.
Marketcap has over 500 billion so far and tether at this point costs 1.09$