The US system is also supposed to be a process of truth-finding, just that we leave the parties to support their own positions as adversaries. Without advocacy, American courts do very little on their own. So far that doesn't bother me, but I'm a lawyer. For someone thrown into the system, there can be an incorrect expectation that the court will automatically act to do justice.
Part of the problem with the adversarial system is that if one party has bad lawyers, you can end up with bad case law as a result of them failing to properly argue their case.
You could end up with one party intentionally losing a case in order to establish precedent that they expect to profit from in the future, because they expect they'll usually be on the other side of similar cases.
Not sure, but I seem to recall a case where Microsoft was on the other side of a suit from where you'd expect them to be, and people were afraid they'd lose intentionally. No idea what it was about or how it ended, though.