I think your first point in the "Why we shouldn't" should be in "Why we should".
Second point in "Why we shouldn't" is a typical shopping question, which is basically prohibited by default on most SE sites for the obvious reason of there being infinite products on any given topic and we're not a shopping recommendation site.
Sure we're built for it! Take a look at other SE sites where they have some questions like that, but on their topic.
We could probably expect there to be a total of ~100 non-duplicate "meta"-questions about preserving figurines, posters, mangas and dvds/blurays, which isn't that big a number if you consider how many ID requests we've sifted through over the years. And it would be actually useful information for a lot of unique visitors, unlike IDs.