I'm not sure if this is intended or not, but it looks to me like when a layout builder created block (aka non reusuable) is removed from a layout, it removes visually from the layout on the edit or view mode, but the block itself remains in the database, as a non-reusable block. This essentially makes an orphaned block, as it is no longer accessible from the UI. This poses a scalability problem, when over time, a site has the potential of have numerous useless rows in the database.
My proposed solution would be to have a nonreusable block removed from the `block_content` table (and related field tables) when removed from its layout, or at the very least providing a way for a user to remove these blocks from the database.
I'm looking for feedback on this idea before putting time into a solution on it. Any side-effects or challenges that could be raised against this?