I imagine scaling of the ID with polypropylene is far slower and lower accumulation than any metal pipe, too (even with water treatments on the secondary side.
I use it for drip irrigation. It is amazing stuff.
Scaling is absolutely lower than steel pipe as you point out. The vulnerable point for scale or particulate plugging is the orifice the water is dripped from. Replaceable or field serviceable nozzles remedy this though.
What kind of application do you work with? Agriculture, greenhouse, garden?
A shameless plug for a supplier is Harrington Industrial Plastics. I worked with them pretty much exclusively for 20 years as they usually were a one stop supplier or at least on the bid list for what I would be working with in the lab, pilot plant and commercial scales. Top tier manufacturers, no Chinese crap.
I have no idea who or where drip irrigation was first put to use. However IIRC, it was Israel that first implemented it extensively in the agricultural application. The desert bloomed.
As I understand it, precise amounts of water can be metered exactly on an individual plant such that the farmer can input things like soil temperature and moisture, dry and wet bulb temperatures, solar radiation, rainfall, plant growth, etc. to constantly adjust irrigation rate to a tight optimum. Farming is quite scientific and computerized now once you step up to industrial size.