I've got 30gb of comics that I would love to put on my Nook via Comixology. Does the Play store allow for the default use of SD media or does it cram everything on the internal memory?
You'll have to download the app and check.
Nook - no option to save to SD Cards.
Most Android Apps from Google Play Store - option to save to SD Card.
So it depends on the individual app and whether it allows saving to SD Card.