profit sharing is a terrible financial decision [...] it's basically a bet against yourself.It's a hedge, which is different than a true bet against yourself (i.e. a short). Semantics aside, surely hedging against yourself is not always a terrible financial decision?
For example, insurance is a hedge. Taking out life/health/car insurance is not always a terrible financial decision.
Taking out a large student loan is tantamount to taking a "long position" on yourself. You are betting that you'll make lots of money in the future, enough to easily pay off the loan.
If that is a good bet for you, go for it. But surely some people want a less risky option, either because they have less risk tolerance or they have lower expectations for their future gains, or whatever.
As another way of thinking about it, profit sharing is selling equity in yourself. If we accept your premise that profit sharing is "always a terrible financial decision", then surely no rational corporation would ever sell equity in itself except as a last resort; they would be financed by debt whenever possible. But of course we can observe this is not how things work.