Astronauts on spacewalks famously have to relieve themselves inside their spacesuits. Not only is this uncomfortable for the wearer and unhygienic, it is also wasteful, as—unlike wastewater on board the International Space Station (ISS)—the water in urine from spacewalks is not recycled.
For the ISS it adds to the launch weight of suits and takes up additional space when using airlocks and in storage.
For a moon/mars mission (claimed use case in the article) it increases your center of mass and your inertia, resulting in more astronauts falling over.
I doubt launch weight would be a huge issue.