20 years ago, Mercurial was not the wrong choice.
- Its internal design was very similar to Git's.
- Its cross-platform support was superior to Git's. (Git didn't get good Windows support until some years later.)
- Its ergonomics were superior to Git's, which was an important factor on its own, and especially important when trying to get a whole organization to retrain and retool around a distributed model.
- (It had a third major advantage over Git that I unfortunately cannot recall at the moment.)
So you weren't wrong back then...
...but Git improved over time, tipping the scale closer to a balanced state. It also had unbeatable author recognition, making it the obvious choice for anyone unaware of Mercurial's advantages, and eventually leading it to benefit from the network effect. And GitHub appeared, greatly improving Git's ecosystem with no support for Mercurial.