[drvd]

Some people think Optional/Either/etc are the absolute cure to a certain sort of problems and -- I speak from experience -- it is impossible to convince them that it's not.

Well, of course, if your end users, the business users, are okay if you present them an "optional result" which might or might not be a result, then Optionals/Either _are_ the cure. Unfortunately most end users are pissed if you tell them that you optionally shipped their purchase or that the refund will either be credited to their CC or not.

[mattnewton]

It's about handling those error cases or failing the build, rather than getting a null pointer exception at runtime that moves execution to some higher part that has no context and little ability to correct the problem, or just crashes. You can still handle it wrong, but you are forced to handle it rather than just, in your example, charging the card and crashing the thread when updating the database that you charged them.