> [the Pilot Metropolitan] uses standard international cartridges
I'm afraid not; Pilot cartridges are sui generis, and not compatible with either Lamy's own proprietary design or with "International Standard" cartridges.
That said, there's nothing wrong with proprietary cartridges per se, given that fountain pen cartridges in general are a pretty niche good. I like Pilot cartridges for being refillable and resealable, especially since Pilot makes a lot of really nice inks that only come in bottles, but unless you're anxious to do a lot of refilling that doesn't really count for much.
I'm afraid not; Pilot cartridges are sui generis, and not compatible with either Lamy's own proprietary design or with "International Standard" cartridges.
That said, there's nothing wrong with proprietary cartridges per se, given that fountain pen cartridges in general are a pretty niche good. I like Pilot cartridges for being refillable and resealable, especially since Pilot makes a lot of really nice inks that only come in bottles, but unless you're anxious to do a lot of refilling that doesn't really count for much.