I've come down to the view that _defining a function using `def` syntax adds structure to a program_, even when it's not desired. It's multi-line, includes an indent and a keyword. It look more like creating a `Class` than a `list` for example.
As a result, in order to define a function _without_ adding structure people fall back on lambdas.
I think the best resolution would be to embolden lambdas with some of the benefits of functions - e.g. multiple lines