Elsewhere in this thread posters are talking about users losing their "life's savings", but you're right perhaps they weren't investing. Maybe they just wanted to park money someplace they viewed as safer than a traditional savings account or treasury bonds.
Presumably this is because there's a trade that promises one side something (stable value coin vs USD) that has another side that offers something different (profits if everything works out, losses if it doesn't?). Kind of like Lloyds of London?
I think the issue is that people are using DAI to leverage what is an "investment" (or gambling, depending on your perspective) in ETH. But this isn't a failing of DAI. DAI merely allows you to leverage an existing position in ETH into a higher risk / higher reward investment, the DeFi way. This is only one of DAI's use-cases.
That's probably not a good idea given how risky ETH is on its own, but again, it is not a unique failing of DAI when people use it in very risky ways. For example, you could take out a personal loan to achieve the same level of financial irresponsibility (as many people did when they used their student loans or whatever to buy crypto).
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