Not so - I decide to forgo my rarely used third ring before I discovered that Sram road and MTB components are compatible.
I'm using a 36/22 x 11-36 combination.
36 x 11 gives me a 25mph top gear at 90rpm. I'll have to be going down a mineshaft to need higher.
22 x 36 gives a 17.4 gear inch low gear - plenty low.
I find the gear progression quite natural and comfortable.
36x11 equals 23.6 mph at 90 rpm. 88.4 gear inches. Sort of quick. But with a tailwind and level ground, you can easily go faster. Almost all down hills will get you much faster than 23.6 mph. I coast down all hills without pedaling faster than 23.6 mph. Vast majority of people would be unhappy without a higher gear.
22x36 low gear equals 16.5 gear inches.
Personally, I'd opt for a 40-22 crankset over your 36-22 rings. Combined with a ten speed SRAM 11-36 cassette of 11-13-15-17-19-22-25-28-32-36. You would have 15 usable gears on your 20 speed bike. Your 36-22 gearing results in 14 usable gears.
One of the problems with double mountain bike cranksets on touring bikes is they do not come from the factory setup like this. Every touring bike comes with a triple crankset and shifters/derailleurs for a triple crank. If a person wants to use a double crankset on a touring bike, they MUST build it themselves. Either buy all the parts and frame and build the complete touring bike themselves. My choice. Or buy a stock bike with a triple and replace shifters, crankset, derailleur. Costly and wasteful.