I wonder why they still offer the Google Play versions as being "DRM free" Is it just Google has more weight they can throw around and O'Reilly didn't want to

I wonder why they still offer the Google Play versions as being "DRM free" Is it just Google has more weight they can throw around and O'Reilly didn't want to 'rock the boat', or was it a technical problem? Apparently the Google Play versions of O'Reilly books are formatted strangely and aren't a direct PDF of the physical books.