Hey Shoto,
I have one of those Japanese Pull Saws.
Yes; they are very easy to use and do have a thinner cut.
But, you have to be careful not to push with any real force, because they will flex very easily if there is any resistance.
I hadn't considered using mine on briar, or iron wood because it is very dense.
But, mine works fine on other types of wood, e.g. Ebony, Pine, and Oak.
You have to be careful with Ebony.... it is hard as nails and will split or scorch easily. It makes for good tampers with some break in period, but won't stand up to high heat for any length of time. It also come coated in bees wax to keep it from splitting. (Don't ask me why bees wax. I don't have a clue.)
Like I said it's a very flexible tool and (as long as it's sharp) cuts most types of wood with relative ease.
One just has to be patient because you can't put a ton of pressure on it.