Not weird at all.
Here's another example: GNOME shell uses JavaScript and CSS, and it's pretty straightforward to understand. Was looking at the code of a plugin to hide the workspace switcher popup and tried a few things to instead reduce the animation time to something that does not necessarity stick around over my windows too long to bother me when I want to view the content beneath. Took and few hours but I got it configured decently, and "live reloaded" it to get the effect instantly. Here I reused my JavaScript knowledge to solve it; if it wasn't so easy due to my previous unrelated knowledge I probably wouldn't have invested any time in it.
Personally I can't agree, since in this case using what you know involves shoe-horning a hacked together and mutated beast into a role it wasn't designed for.
It's true what you're saying, JavaScript wasn't designed for this, and chromium is being repurposed for something out of it's scope too. But hopefully it will evolve with time in the right direction, my honest opinion is that it has the potential, mainly due to it's popularity, there's and huge amount of resources and hours people are willing to invest it it.
