Because they're cheap, get the job done, and looking good wasn't a requirement when the committee approved them. Why else?
Really only special forces need camo. For everyone else, most of the value is symbolic. It's psychological trick to try and get peacetime base personnel to retain at least some discipline.
I still had a poncho like that in boot camp for the US one. After that I never seen it again. The 2nd pic, I seen pics of the boat cloak, but never seen one in real life.
Do pelisses and coats worn as cloaks work? This should be limited to non-commissioned officers and upwards, I think it just looks stupid when the rank-and-file has fancier aiguillettes than what generals wore back in the day.