The problem is that if you want to provide a full-featured file picker, and not rely on Google's limited browser-based version, your app will require the full "drive" scope. (We do, and we do, for our InDesign-to-Google Docs connector plugin.)
If you use some of the lower-tier CASA labs, it's not that expensive (4K/year), but it is definitely a nuisance for a pure desktop plugin like ours that has absolutely no cloud component (other than connecting to GDocs).
If you use some of the lower-tier CASA labs, it's not that expensive (4K/year), but it is definitely a nuisance for a pure desktop plugin like ours that has absolutely no cloud component (other than connecting to GDocs).