The situations it's intended to address are things like this:
Bob meets regularly with known members of Mexican drug cartels, but doesn't actually seem to be involved with the illegal sale of drugs. Bob files his taxes every year and makes a modest income. However, every day, Bob drives over the border at El Paso in his car with a million dollars of cash in a briefcase.
If the DEA stops Bob, he asserts that the cash is his. Since it's not obvious that Bob has actually committed a crime, shouldn't there be some mechanism to allow the obvious profits of crime to be confiscated without having to convict Bob?
A lot of reasonable people think the answer to that is "yes"; but it is apparently hard to create a mechanism that doesn't also result in the police confiscating your car because your friend that's riding with you has $500 of cash, a bunch of empty baggies in his pocket, and prior drug dealing conviction.