I heard there are people army retired in the evolution of the coin.
And I think they are really keen on the value of USDe as dollar. So this is the only reason I can see.
Maybe another thing is that only those people start buying all those cheap coins from all over the exchanges and they really kept it until the price goes up, because it would make the price increase due to rareness, somehow. Then they started to sell it slowly but patiently, this way none can dump it and the price has to stay high for others to make profit This is also a way of marketing.
Maybe !
One of the answer is like this:
The coin used to sell at 500 satoshi when it first came out, then almost hit rock bottom at 20. But with steady support, and awesome devs things are picking right up. After the halving of payout amounts, KGW, and forking, USDe's support almost quadrupled. And I bet being on more than a few exchanges finally didn't hurt either. So in my opinion slowly but surely the coin is moving in the right direction. The more online stores will accept USDe as currency the more exposure, popularity as well as value it will gain. So I imagine getting more exposure is the key to the success of USDe!