TLDR:
1. Strong foreign language skills from overseas missions.
2. It's easier getting them security clearances since they don't use drugs or alcohol.
replies(6):
From the members I have conversed with, they are forbidden from using caffeine.
> It took a great deal of time, repetition, patience; no small amount of hope and faith; lots of reassurance from my wife; and many liters of a diet soda that shall remain nameless.
[0] https://www.churchofjesuschrist.org/study/general-conference...
Clarifications as to what the 'hot drinks' section means has come over time, generally being shared during the twice-annual General Conference. The most prominent call came in 1921.
You can read more about it here: https://www.churchofjesuschrist.org/study/manual/revelations...