This would be more fun if they're actually serious in making this.
As it's based off the BMP-3 platform, it's not going to cost much and production can be seemless.
The gun is AA meant to deal with drones and other low flying targets. But it can be turned against ground targets and it uses air burst ammunition besides. Besides it's a 57mm, that's a lot more punch than a 30mm. The vehicle can give some defense against drones and can be used to deal with targets on high rise and elevation.
As the BMD-4M is getting programmable timed air burst 30mm, I will assume it's safe to say future batches of BMP-3, BTR-82A, BMP-2M, BMP-1AM, and the BMPT-72 might get it pending upgrades on their fire control systems. The ammunition will not work on older models with a modification on the FC. Have air burst ammunition can go a long way in turning the 2A42 and 2A72 30mm guns into legit AA, along with night vision.
To answer the question, maybe the BMP-2 or 2M has an elevation of 75 degrees so it wins. But what's elevated on the BMP-3 happens to be a 100mm gun, not a 30mm. It can lob a 100mm shell or an ATGM right at a high rise. On top of that, the gun can be used like a legit howitzer with indirect fire and having a drone adjust for that fire.
