Why ?
I am touched that you are answering on a Saturday! Thanks a lot.
I guess your "why" concerns the reason why I am using the webview and not blocks.
Sorry I forgot the word "complex" before UI, I meant a "complex UI". I am more used to using HTML/JS, than the blocks. Also, one part of the UI is a customizable table with many rows/columns which is very easy to implement in JS, and less so with blocks.