[suresk]

They don't necessarily force the developer to deal with the problem, unless you're talking about checked exceptions (which are a whole other controversial programming opinion). What they do accomplish, in my opinion, is more deterministic behavior and easier debugging.

If you rely solely on return codes to indicate an invalid state and the caller is free to ignore the error codes, it makes it much easier for the program to continue on doing invalid things - this is akin to wrapping everything with try/catch blocks and suppressing exceptions. Even more, when you do realize something is wrong, a system utilizing exceptions is generally much better at propagating information about the original problem.