It's the industry standard because passenger guys get 60 landings/90 days and 800 - 900 or more hours of flying each year. I sure would like to know what our averages are. I know I have averaged flying domestically for 18 years only about 350 hours/year and usually in the 20 landings/90 days.
Even though it's a hassle to go to the sim I'm glad that I get to do it twice a year.