Carrying Pressure Cooker

I'm not sure that I understand your reasons for considering it. You mention fuel efficiency. Why do you want to save fuel? To reduce pack weight?

If you are committed to trying unorthodox kinds of backcountry cooking that require hours of constant stove operation, and you will be doing this at high altitude, and your trips are long (weeks), and you just want to reduce fuel consumption as much as possible, this seems like a reasonable idea.

If you will not be at high altitude OR your trip lengths are not extraordinarily long, you will almost certainly save a lot of weight by using a Jetboil-style heat exchanger pot instead of the pressure cooker.

If you won't be at high altitude AND your trips will be short, your lightest option is probably a conventional pot.

This 1.5 liter, 2 lb pressure cooker is roughly 27 ounces heavier than a lightweight 1.5 liter pot. With 27 ounces of fuel I can prepare 80 one-person hot meals. The pressure cooker will have to reduce your fuel consumption by that amount just to equal the INITIAL (trailhead) weight of a conventional system. It will have to save much more fuel than that to really make sense from a fuel efficiency standpoint, because a less efficient system with a lighter pot will decline in weight throughout the trip (as fuel is used), whereas a more efficient heavy pot declines less and is still heavy at the end.

If I am misunderstanding your "fuel efficiency" comment, and you actually don't care about fuel weight, go for it. If you just want to try some adventurous and ambitious backcountry banquets that require hours of cooking, great. I'm just suggesting that fuel efficiency alone is probably not a good reason to choose this pot.