Businesses do not need to be in the business of selling images in order to have a need to store images.

I just feel safer using Dropbox or Glacier. Flickr seems more like a social network, specialising in photos, and I wouldn't feel comfortable about using a service like that as a backup. As a business, the TOS are just not clear enough about what I can and can't store.

True, It's just the first thing I think of when "photos" and "business" come up.