The ability to put down a 1:1 or 1;2 ratio of N:K is an advantage of a custom blend liquid. I also like having control over the source of the K. My soils are contaminated with chlorides as is. I do not need to add more in the form of potassium chloride.
Drought resistance is a good reason to maintain more than adequate levels of K in the turf. In a place where you cannot have a lawn without irrigation, this matters. It makes a difference between the lawn that needs watering every 4 days or the lawn that must be watered every day or else. I know what happens to lawns that get mostly urea and trace amounts of potassium chloride. It ain't pretty compared to a lawn that never sees urea and gets enough K and micronutrients.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738