The alternative would be nasty - let's break out a protracted set of functions, variables, loops, etc to process this piece of text in a more "readble" way? No thanks - let me bang-out the regexp and be done.
Also - At least Perl uses a normal open/close (braces) to begin and end a scope - unlike Python - which relies on the number of leading spaces. (I've been using Python for years - can handle that - but still think it's a very bad idea).
For me - Pearl's biggest downside has been that the world has simply gone to Python largely, and so have I.Whereas I used to love Perl, I find it hard to keep switching back-and-forth.
That being said - I miss the ease at which Perl can fork a subproces, then scrape and parse it's output. Yes you can do this with Python - but it does take more keystrokes. From a linguistics point of view - it comes down to Information Density. Thus, we can argue that Python looks cleaner, but Perl's code is denser.
"We learn from history that we learn nothing from history." -- George Bernard Shaw