Does SVB Visibility (blocking on load) not work?

Setting up level streaming for our game, we want all the levels loaded but hidden, and to have level streaming volumes hide and unhide levels only. It’s implied that this is an option in the level streaming volume “loading and visibility or just ****visibility (blocking on load)

Even with this option selected and levels set to be initially loaded, the level streaming volume seems to actually load and unload the level, as Event Begin Play events fire in various Blueprints within the level in question, when playing in editor.

In this thread…ility-troubles the OP asks the same question in the last post of the thread, but unfortunately Tim Hobson never replies at this point.

Edit: So it looks like in Level Streaming, unchecking “Use Background Level Streaming” fixes this problem, and also gets rid of hitching. Is there any explanation of why this is? It seems like unchecking such an option would lead to the opposite of giving us better performance, is there an explanation of what this does?