Yes, mshtml was insanely powerful. As an undergrad I was surprised how easy it was to build capable UIs with powerful visual effects[1] using mshtml and JS. Even for C++ Windows apps.

It took a long time for this to become a cross-platform reality, but it did inspire me to ignore distractions like XAML and focus on the web.

[1] https://learn.microsoft.com/en-us/previous-versions/windows/...