Because sometimes I want to have logic that spans multiple lines and I don't want to assign it a name. An easy example might be something with a `map` or a filter. For example, in JavaScript

    [1,2,3,4].filter(x => {
        let z = x * 2;
        let y = x * 3; 
        let a = x / 2; 
        return (z + x * a) % 27 == 2;
    });

Obviously I know I could name this function and feed it in, but for one-off logic like this I feel a lambda is descriptive enough and I like that it can be done in-place.

You're free to disagree, but I think there's a reason that most languages do allow multi-line lambdas now, even Java.