Viability is not permanent
Seed stored well still ages. Preservation is therefore a maintenance activity rather than a storage decision: material has to be checked, and periodically grown out and replaced, or the collection slowly becomes a museum of things that no longer germinate.
Grow-outs cost something
Every regeneration is also a small selection event. Grow out a hundred seeds from a thousand and the population you put back is not quite the population you took out.
Handling that honestly — planning for it, recording it — is part of what separates stewardship from storage.

A collection that is never grown out is a museum of things that no longer germinate.