However, changing it now doesn't seem that important to me. 

(And I've used lambda's as default argument - I was moving data from one database to another, and wanted a generic method to switch out column names that defaulted to the same header. So it became a lambda x:x function by default, but you can provide any function that takes and returns a string and change the column names. This was last week.)

And lets be real - adding a new keyword is something to be done extremely sparingly. lambda could have been avoided by re-using def. And no, it being the same keyword is an advantage, as they do the exact same - they create a function. It's the same reason as we use if condition: