K wrote:
But how does a donation of commercial or antipodean seed help preserve
Latin American diversity?

I suppose it's about diversity, not specifically latin american
species. It's also fun to make contacts around the world. You wouldn't
beleive what I've received through the post in the last 10 years, from
strange beans to sun baked deer skull, from waffer thin pecan nuts (to
die for) to soil samples. It's all about sharing. If the seeds are not
appropriate I'm certain that they will be passed on to someone who will
enjoy them, especially if it's vegetable seeds.