Well, you're right. You have to set up your gearing properly which I've done and helped do for dozens of bikes. I does take getting used to and I can dbl shift in my sleep, while snoring in the rain at night with headwinds.
While it's a arguably a bad habit to get into and it could take some time to master, it sets you up with a true 15, 18 or 21 gear bike. I've custom built my freewheels for years. Mostly the bikes today are set up with so many gears that you never know where you're set and many folks don't want to shift the front chainring for some reason.. I guess I equate today's drivetrains to automatics. You don't have to think about it. In this case he could go with the following, while not perfect it gives you 14 distict gears with favorable 1/2 step and the triple gives you 5 more distinct gears:
42/36/22 with 11/12/13/16/20/26/34
Don't get too hung up on that "plus granny" or "plus alpine"; it just means a very distinct lower set of gearing on the third chainring which doesn't figure into the 1/2 step part.