If it works for you, keep doing it. I just go by what I've noticed when I try different things.
Do you have a Window in your MES?
Liquid in the pan could be a good idea for some smokers, but not for an MES. IMHO
I used to try Beer, Apple Juice, Water, and other things in the water pan (6 years ago). I got no added flavor to any meat, and all it did was add more humidity to the cabinet that already has too much humidity.
The glass window in the door of an MES proves there's too much moisture inside when the condensation forms & runs down the inside of the window----And that's without adding anything to the water pan.
It also affects the burning of the AMNPS.
Like I said, If anyone is happy with putting liquid in their pan, they should keep doing it.