I also recently found ParrotSec OS I was using it as my main OS for about a month or two. I mostly used it because it is a Debian fork and it featured the latest of any programming language I wanted, which is great for me. I stopped using it because it felt cluttered for me to have so many different pentesting type of tools. It had built in support for connecting you to Tor and forcing all connections to go through Tor out of the box. A lot of things I don't need but others might find interesting. I may return to it now that they're building a flavor for developers. It comes with a few text editors out of the box including Atom. I wish Whonix would compare ParrotSec too. :)
Used parrotOS 2 years ago. I think it was newish then. Liked it a lot. Was fairly polished then. What do you use it for and what features do you like most?
I really just used it for programming. I loved having the latest of any programming language compiler / interpreter when I used it. Something I don't see in Ubuntu / Debian flavors I try. I'm using ElementaryOS atm because I like how minimal it is, I bring in what I need after installation. They have a "Studio" flavor that I wanted to try, but the Network manager seemed to be broken from install, I remember installing KDE from the ParrotOS based I installed initially and had the same problem, the networking wireless icon is completely missing. If they fix that on their "Studio" release I may start using it again. I enjoyed it overall. My only other issue was that I didn't need the "tools" ParrotSec came with. I would definitely recommend ParrotSec OS overall.
Linux Distros are always behind, and in the case of Ubuntu / Debian Python is locked into whatever they release because the OS actually relies on whatever version of Python they released the OS with, if you upgrade to latest and greatest on Debian Wheezy e.g. you might find your OS has bugs that Ubuntu 16.04 doesn't see (both use similar packages).
I guess it's mostly for interpreted languages. Try installing (not that I use it) Eclipse the Java IDE as another example, it's usually dated enough. This is probably why people use bleeding edge distributions. I guess in the case of compilers it's not as bad, though you can't usually get the latest and greatest Go compiler either, you have to grab the .deb off the website or use other tools. At least Rust just hands you rustup so I don't need to worry about this in the case of Rust, but with other languages like Python it's a concern of mine.
Edit:
Link to ParrotSec OS website. https://www.parrotsec.org/