You can still get a dollar or a dollar's value for it. That's what it's for and that's all that people care about.
I'm really amazed it's continued to grow but it's just another illustration of the willingness of people in this space to make the same old mistakes, and some sexy new ones.
i'm not amazed really since it is expected. tether grew because it is filling a gap and will continue to grow as long as that gap exists.
this gap is two things. first is the need that altcoin traders have for something that has a "stable" value so that they can escape to whenever bitcoin rises or drops and causes the mass dump of altcoins. and second is another need that altcoin traders have for an easy, cheap, no KYC way of transferring value between exchanges.
if you compare the times when tether growth peaked with the altcoin market pump and dump periods you can see that the major rises were:
1. 2017 mass altcoin pump when every single altcoin even the long dead ones worth less than 1 satoshi got pumped
2. 2017 ICO mania where thousands of ICO were being created every month or so
3. 2018-2019 mass altcoin dump which was the reverse of #1
4. 2018 mass ICO death which was reverse of #2
interestingly enough tether was added to ethereum network to exactly be used for pump and dumping ICO tokens during the ICO mania by the end of 2017 and grow a lot during the ICO death spiral next 2 years.
this is also why i always found it very weird when people kept linking tether with bitcoin price when almost all of tether's volume (near 98%) and its main purpose is for altcoin trading.