Mainline water backup valve

[Benbear]

I have this in-line backup valve in our home.,.Mainline #4963 Full-Port Backwater Valve. I am searching out views on this gates engineering. I am trying to understand why this open gate concept is better than the traditional “ closed gate backup valve”…I have one on a secondary drain. There is now an upgrade to this unit and am considering it as it has the ability to manually close…which I like. This backup valve is very accessible in our basement which allows easy access for maintainence and repair if necessary. I will call the manufacturer, however unbiased views are sometimes more valuable. Thanks