'Ad groups' goal

I'm not quite understand what's for 'Ad groups' field.
" Ad groups:
----------
Ads can be organized into groups. For example, you may have a group called
"Text Ads" and another group called "Image Ads." You could then assign your
text ads to the "Text Ads" group, and your image ads to your "Image Ads"
groups.
"
If I read it right you can grouping ads, but it can be replaced via Taxonomy.
If you decide to develop 'Ad groups' it will be less convenient to use.
- weight should be changeable (using taxonomy, you already got that)
- it's good to have possibility to change from single to multiple choices (using taxonomy, you already got that)
- if you don't want to use groups, you should have possibilities to hide it from the form to make it simpler (using taxonomy, people can use this feature or not)
- if there will be many groups, you should be able to change widget to dropdown or autocomplete to make it easier to use (using taxonomy, you've got already that, if not)
- if you want to create View via Views which show you specified ads from specified group, you should implement Views integration (using taxonomy, you've got already that, if not)
- using Taxonomy, you've got already support for search engine, etc, etc.