When I create custom habits, they are severely hamstrung in terms of what can be shown to the client on the display page. Most clients do not swipe to the next page and do not understand how habits work. They simply see a habit name and mark it as completed or ignore it.

When I create a new exercise, I can't choose the thumbnail used and there are no looping video excerpts. I also can't make a grouped left/right split version of them.

Both of these are examples of how the built in content has powers/features that are not available to us when creating custom content. Custom content should behave just the same as the built in content, if not be even more powerful/capable.