I find the fact that beer pipelines have their own color designation in the map legend intriguing. Are they common enough outside of breweries to merit singling them out?
There are two beer pipelines in Belgium: https://overpass-turbo.eu/s/2isf I think the fact that they're in the OpenStreetMap data at all is enough to give them their own color on the map.
I suspect that it is more about being a cool fact than being common.
I know there's one in Bruges, which is mapped on here: https://openinframap.org/#13.22/51.21001/3.22418/A,B,I,L