[franga2000]

Simple: it's because it's the most widely supported system.

Want to recommend me a better VCS? Feel free, as long as it has a cross-platform open source client, a nice GUI, is supported in my IDE, there's a company offering to host repos for free along with a nice web viewer, it's supported by a CI system comparable to what I use now (including giving me free time on shared runners)...

[midenginedcoupe]

Isn't that just a reflection of its current status as the defacto standard, rather than an explanation for how it got there?

I've been in two teams that spent time to evaluate revision control systems on their own merits and Mercurial came out on top both times. At that time, bitbucket supported it, as did IntelliJ. Ironically I can't vouch for whether that was the right decision at the time as the network effect meant they went with git anyway!