I can appreciate the concern. I’m not too sure the manufacturing would create much more waste long term. A single use syringe made mostly of plastic probably generates as much cumulative manufacturing waste as an aluminum bodied reusable pen over the pen’s lifespan. Granted, I’ve only been using the three I have for about 4 months, but one is used daily and the other two weekly. They show no signs of wear so I hope to get many more months if not years from them.
I will say that this hobby does generate a surprising amount of waste in general. Especially those of us with daily pins.