IME, it's great for building full standalone applications. I've used it to build several internal tools for non-engineers. A tool like that doesn't need to work with a screen reader, or have native buttons, etc. It needs to be easy to build and iterate on.

This isn't to say a tool for non-engineers should have animations to make it useful. ImAnim should probably be used sparingly, if at all.

If you need the features of a full GUI toolkit, then by all means use Qt or wxWidgets etc, but that's a very big jump in project complexity.