Lenses have disadvantages and advantages. Mostly disadvantages when used in Chinese LED panels.
This is why:
You have the LED chip > optical lens > tempered glass cover.
Each layer of glass (or plastic) the light has to go through, it loses light. 10% at the optical lens, and 10% more at the tempered glass cover. You get 81% of your light.
If the LEDs are already 90 degree, there is no need to add additional 90 degree lenses. Most LEDs from China start at 90 degrees or 120 degrees. Lately mostly 90.
If you add all 60 degree lenses, then you have too much intensity and much less of a lighting area, and you will get leaf bleaching, even with smaller than 200 watt LEDs at 24" above the plants can cause bleaching.
If you mix some 60s and some 90s properly, or other degrees between, then you'll get some advantages of using lenses.
The main reasoning behind secondary lenses is so the grower doesn't have to rely on reflecting light back to the plants as much. It's a really good idea if the lenses used were the proper degree, and even better if the tempered glass cover can be removed.