We live in a fragmented o/s world. If you're someone like me then you've got a Macbook from the office, a Windows PC for games, a Linux workstation for compiling code, a FreeBSD server, an OpenBSD router, etc. When you're dealing with so many different systems, sometimes just having something as simple as a sed command that works reliably the same seems like an impossible ask. Now we've got an entire app platform that works on the lion's share of PCs/servers in a small 1mb file.
It's also a question of being able to distribute code. I used to work on the TensorFlow team. We were tasked with building an open source library that people on pretty much every platform imaginable would use. It broke my brain just how difficult it was for us to ship open source binaries that actually work and don't cause an avalanche of GitHub issues. Even just working on more than a few Linux distros felt like an impossible ask back then. Now that I've figured out how to do it for every distro and seven operating systems total in just one file, I wish I could go back in time and use tools like redbean and Cosmopolitan Libc to fix all the things with TensorFlow that I wish I could have done. It'd've been a different project.