Got this just a short while ago:
Your interior and cover files for xxxxxxxxxxxxx, #xxxxxxxx meet our technical requirements for printing.
The next step in the publishing process is to proof your book:
FOLLOW THIS LINK TO GET STARTED:
Which I assume means the embedded fonts in the paperback cover are A-okay. There was no additional message about corrections made for me, on my behalf, or anything like that, so this answers the question of whether or not the PDF cover files would be accepted by CreateSpace with fonts embedded instead of being flattened into the image. Should’ve guessed, really, but I just wasn’t sure.
I’ll be ordering a proof to check this out and compare the quality of print to the covers I didn’t embed fonts for (sending only a flattened image PDF to CreateSpace), and scouring over the digital proof from CreateSpace. If the quality of the text appears better, I’ll definitely be doing this extra step from now on. If it isn’t any better, then I’ll just use GIMP, and only add Elements into the mix when I need to use a font that brings out that unfortunate GIMP text rendering (?) bug.
Also, I discovered something with this round of paperback creation. I’ve consistently had a problem with my PDF cover as exported from GIMP having a transparency that CreateSpace fixes for me. I’ve not had that problem this time. The difference? This time when GIMP popped up the little message during the PDF export, I unchecked all the little boxes for things GIMP was offering to do for me during the export. And now, no transparency warnings from CreateSpace for the three covers I exported directly to PDF from GIMP. Pretty happy to have figured that out. I was exporting a completely flattened image to PDF so there shouldn’t have ever been any transparency anyway, but obviously something GIMP was doing during the export on my behalf was creating it.