The crippled nature of Python's lambdas are a big weakness of Python. They sit in a no-mans land of providing half a solution but being too crippled to actually to clarity / improve programming style.

I much prefer languages that go all the way and give you full integration like Ruby, ES6 and Groovy. For example, in Groovy closures just blend completely into the language:

    [1,2,3,4,5].grep { it > 3 }.collect { it * 5 }

Compare to python is almost incomprehensible:

    map(lambda y: y * 5, filter(lambda x: x > 3, [1,2,3,4,5]))

But breaking this into functions reduces to an almost silly level of verbosity. Of course, idiomatic python would write this as a list comprehension, but that is just proof that the lambda construct is broken, and the list comprehension is a band-aid and doesn't scale up to more complex scenarios.