Problem:
The user has created a reusable block from a view block. Then he used it on a different page and he was not able to convert it to a regular block anymore.
Solution:
We convert a Reusable block into a regular block in order to edit it and have the edits only in this place. That can't be performed for the view block. Because the view block uses a view. When we edit a view block, we are actually editing the view. You can reuse the view elsewhere without first converting it to a reusable block. And if you edit it, the edits will be propagated everywhere where the view is used. Because, the updates are performed against the view, not its view block.
I won't recommend making a view reusable. It is already reusable, by design. But, if you need a similar view with slight updates, you will have to create it from scratch.
