You definitely need a signed(certificated) .apk-data for releasing at google play. A debug-file isnt allowed to be released.
But actually C2 doesns support this (as far as i know). And i wouldnt think about, to compile and generate a key within a cloud service.I ran some smaller test with phonegap just for fun, but compile with it to make seriously money?! Never ever....
So, as there is actually another (more or less) big gameproducer-software releasing their studio edition, Scirra could need akp export too.That would be epic!!!