I agree, there's no indication that supplies are limited or that anyone will be disappointed.
A garden isn't ever complete and static, it goes on evolving and developing. Plants die for all sorts of reasons, or simply don't thrive in the places where they find themselves, so there's a constant need for replacement.And sometimes there are plants that just have to be got rid of, like the enormous conifer we've just had removed, thus opening up a new area for further planting.
Like other gardeners, I try not to waste anything, and often give away spare plants to friends and family.Last year I ordered the free petunias, and gave half of them to friends who produced such lovely pots with them, they put mine to shame.
It's not in any way similar to acquiring unnecessary quantities of clothes, books or other consumer goods, because Nature, with our help, is capable of producing an endless supply of plants to enhance our gardens and our lives, without any finite resources being used up. And most people on this forum, I'm sure, will cherish and care for their new baby plants, not throw them away.