Go on. Do the maths. Yes, we all understand that a pot is unnecessary and unwise.
As I understand, there is an internal 10k pullup to VCC on VO pin. So a single external resistor from VO to GND is all that is required. e.g. 470R
This means that approx 500uA is drawn from a 5V supply. (5.0V / 10470R)
If a 10k pot is wired to VCC, VO, GND you will have an additional parallel load on VCC of approx 500uA.
And the same contrast will be be set when the pot is about 235R / 10K.
Yes, the adjustment range is only a fraction of the pot.
If you use a 1k variable resistance instead of a 10k pot you can adjust over the full range of 0 - 1k. Easily setting the 470R typical value.
Compare this "extra 500uA" with the typical 5mA operating current of the LCD module.
Now compare 500uA or 1000uA to the typical 20mA - 50mA drawn by the backlight.
People have been using 3-terminal pots for the last 30 years.
However many times you repeat the mantra they are unlikely to change.