Hello Gavin and Charles,
Charles, I understand they are used for Betal Nut. Others may advise further.
Peurawot come in very different sizes and blade/hilt configurations. Thus, I have a difficult time to see it as a specialized tool. I haven't found any historic records that mention that peurawot are limited
to working pinang (betel nuts). Given that there is a broad variety of examples (from basic to high status, small to large, different edge/hilt configurations), I reckon it originally was more like a general utility knife with the main sidearm and the rencong taking over the primary and secondary weapon function, respectively.
It is obvious that the highly decorated status peurawot for nobility and other luminaries were important parts of the attire. I have no qualms to accept that in priviledged social strata these may have been mainly or possibly even exclusively utilized when chewing betel (pinang); with mere mortals, however, it seems to me that the peurawot was a Aceh piso: cutting anything that needed to be cut including the socially paramount pinang usage...