If you've done a lot of things in awk before coming to Perl, you'll appreciate why it can be useful not to use strict.
I admit I haven't, but if you mean oneliners, then yes, those are usually written without strict and warnings and it leads to more concise code with its own kind of beauty. At least in my mind, omitting strict and warnings in oneliners is usually acceptable because they are so short that proofreading and testing them is a relatively simple task.
(OTOH, roughly 95% of the oneliners I post here I actually develop with -wMstrict turned on, only to then remove the switches once I'm satisfied the code works, so it gets shorter and fits on one line. An artifact of this that some might notice is my abuse of $a and $b due to them being exempt from the checks...)