You have to remember that the Browns are forced to spend to the cap floor, which they are nowhere near. This trade, which can be legitimately viewed as a waste of money in real terms, benefits them as they are not forced to enter into bad contracts to reach the cap floor - bad contracts that may screw them in future years. They have to spend the money either way, might as well spend it on someone they're not obligated to commit to for more than a season.
Playing the short game, this benefits them by coming closer to hitting the cap floor without committing to anything beyond 2017. In the long-term, it *may* benefit them, depending on what they do with their 2017 6th and 2018 2nd.
Any contributions Osweiler makes (assuming he's not just cut) are a bonus.