Perhaps it is how you design the KM HTML Prompt.
Here's a great example by @DanThomas:
Bootstrap 3 + Auto-Complete HTML Prompt Example
I don't see most of those issues in Dan's macro.
For me, the real power of the KM HTML Prompt, that can't be duplicated by a stand-alone HTML file, is the tight integration with KM Variables, as Dan shows:
- Initialize form fields with KM Variables
- Populate form field selection data with KM Variables
- Auto save the user entires to KM Variables.