ad 2: Brave takes a 30% cut of the add income. The adds you block are targeted adds, thus they yield a higher income. Besides that there are usually service fees for converting your BAT to other currencies.

The entire service is opt in making it also not guaranteed for the content creator to receive the reward.

This should lead even in the best case to a notably worse outcome.

ad 3: https://outline.com/fJm5C3

ad 4: i explained the issue in my other response.