Often when you're dealing with a value that may be null, you might want to do a series of transformations to it that may change its value or type, and may even return null themselves. Optional lets you chain these actions together without concerning yourself at every single step whether or not the value is there until the very end.

Let's take this back to map/filter on lists. Remember the bad old days when you didn't have map and filter on lists? If you had some code that iterated heavily and then you needed to add another step you often ended up refactoring a lot of manual for code that explicitly handled iteration logic. Now with streams you can just chain another call onto the same stream and as long as the types match up you're ready to go test it. Optional gives you the same thing, but instead of working with lists it handles values that might be missing.