AFAIK, there's a difference between MSHTML (internet explorer) and EdgeHTML (edge / trident). But even then, Edge can be somewhat lacking depending on your use case [1]. For simple apps that just need a simple UI without spending time developing cross-platform, this solution is great! Unfortunately the projects I've had to develop require newer features and/or performance lent by using the Chromium Embedded Framework that simply aren't possible, even if Edge was available.
In UWP yes, but not in Win32. Win32 has always been stuck on IE's MSHTML.dll controls, up until either XAML Islands for the WinRT-based EdgeHTML (coming soon, in preview today) or "Webview2" [1] for the Chromium Edge (coming soon, in preview today).
So that means only 25% of your users will still have IE since they never upgrade? Then you have corporate environments where IT held back Edge because internal business software requires IE. (Yes that is still a thing. Yes you can install them both. Yes, IT will still do that.) Then you have systems where some badly written installer broke the native web view but the user isn't noticing because they only use Chrome.
