Everybody seems to be completely missing the point.
The $9.99 plan comes with 20GB of online storage.
The $19.99 plan has 1TB of storage.
So you're simply paying an extra $10/month for 980 GB of storage, which for those who need it (Lightroom CC users with large collections perhaps) the price may be quite reasonable. For those of us who don't use the cloud for photo storage, we don't need this extra space, so we don't pay for it and we stick with the cheaper (non-storage) plan. Easy.
The $9.99 plan comes with 20GB of online storage.
The $19.99 plan has 1TB of storage.
So you're simply paying an extra $10/month for 980 GB of storage, which for those who need it (Lightroom CC users with large collections perhaps) the price may be quite reasonable. For those of us who don't use the cloud for photo storage, we don't need this extra space, so we don't pay for it and we stick with the cheaper (non-storage) plan. Easy.