Ambidextrous Charging Handles.
It seems the trend of yesteryear to make an AR charging handle as large as humanly possible has somewhat subsided. The idea that the latch needed to be 900% larger than the stock design has dropped down to about 300%, but the current trend is to take all that mass off the left side and add it back on the right side under the guise of making it "ambidextrous." I put that in quotes as the factory charging handle is already ambidextrous; allow me to explain.
When we run the charging handle, for whatever reason, there's a pretty simple set of steps.
1: Rotate the rifle so that the ejection port is facing the earth.
2: Grab the lever and sharply run the handle as far back as it will go.
3: Leave go of the lever, allowing the rifle to work as intended.
Notice the orientation of the factory charging handle lever at the end of step one. It is facing upward. Notice how I never mentioned which hand is on the grip and which hand is going to grab that lever that is now on top of the rifle facing the sky? That's because it doesn't matter. We don't change any of those three steps regardless of which had we are firing the rifle with. Once we point the ejection port downward, allowing gravity to assist with every conceivable function of that port, a stock charging handle is in the most prominent position it could be in. Why would manufacturers find the need to add a second latch hidden underneath the rifle?
Marketing. A simple way to get folks to spend money on gear instead of training. They offer a gear solution to a "problem" that is solved on the first day of any rifle class by demonstrating the proper technique.