In a first, an American woman used a suicide pod to take her own life. The process took place in Switzerland. It’s done by pumping in only nitrogen gas, so the person will lose goes dizzy, loses consciousness and eventually dies. Enter futurama memes.
Good point you and others make about airtightness.
For the manufacturing, I’m primarily thinking about how assisted suicide is illegal in most countries, so the ability for anyone to make it, and to make something small, may have some value versus a large, hard to transport device.