Up until now, I did not know this was a thing

Obviously, there are lots of places to get this stuff but here's a link to HD's page https://www.homedepot.com/b/Plumbing-Pipe-Fittings-Pipe-PVC-Pipe/Furniture-Grade/N-5yc1vZ1z18i41Z1z1b5ho

Advantages: Colors, lots of colors. UV resistance, usually higher strength than generic plumbing PVC

Quote:

What Makes These Pipes and Fittings Different to Standard PVC Pipe and Fittings?

Furniture pipe and fittings are manufactured with a formulation with added UV stabilisers that, as well as increasing their life span outdoors, makes for a more ductile material. This makes them physically stronger and less likely to crack under physical pressure. With the exception of snap clamps, which are UV stable for approx. 2 years.
These parts and pipe are manufactured without any manufacturers' markings, making them much more pleasing to the eye.
The sockets of furniture grade fittings are more extended than normal pressure sockets and chamfered on the end, which gives them additional support, as well as improved aesthetics.
The finish on furniture/display grade fittings is more glossy than standard PVC pipe, and is protected from scratching during manufacture, packaging and transportation.
https://www.plasticpipeshop.co.uk/Display-Furniture-Grade-PVC-Pipe-and-Fittings_c_2588.html