I was recently looking at pics of that ball turret and was surprised at how limited the view out seemed to have been when you allow for the solid panels and framing, all the gubbins inside, and the fact that the gunner was on his back with his legs scrunched up.
May have been ok in broad daylight when you could see ‘em coming from miles away, but not so useful at night. Maybe that’s why 214 did away with them!