Does Anyone Use A Pocket Scale?

At home, I use the kitchen scale to measure everything that I eat. Sometimes, I can sort of eyeball an amount, but always check, just in case.

However, when I go out to eat, or go to a friend's place, I find myself estimating how much is going onto my plate.

Sometimes, if I've packed half my meal and brought it home, I'm surprised at how my estimations were incorrect. I might be over estimating at times (causing me to have a lower Protein and calorie intake), or under estimating (so I end up with a higher calorie intake than I should have).

I've thought about getting a pocket scale, so I could use it when eating outside.

Does anyone use one? Is it awkward and difficult to use? I'm open about the surgery, so don't mind people asking questions or looking at me weirdly.