nostr:npub1p36pqtsd7as3a8qcqn2tmm3480acgqngaez0mvvta9vkwmcfzg2qduh2h0 I know of plenty of people who use it, in fact there are rather popular brands of iron gall advertised specifically for FP, so it must be a rather popular choice.

The main reason to use iron gall is it is perminant with good writing characteristics. Since it is safe in a pen with gold nib there is really no reason not to use it honestly.

That said I have since moved over to pigment and carbon based ink. The carbon inks have better writing characteristics i find. The main disadvantage to pigments is that they tend to stain clear demonstrators where iron gall does not.