i agree..
I know sometimes people see the cad plated hyd adapters and think htey are brass.. but no way i'd use brass in hyds. hate to use black iron even, unless on suction sides.. etc.. or NP returns...
plus.. many 'plumbing' adapters don't have the neat features you need / want in a real hyd adapter.. like for instance.. a swivel fem pipe fitting that nees that special concave beveled lip on the male side to actually seal, since in that union, it's not a thread sealing, but rather a mating machined surface.. etc...