CC0 enables scientists, educators, artists and other creators and owners of copyright- or database-protected content to waive those interests in their works and thereby place them as completely as possible in the public domain, so that others may freely build upon, enhance and reuse the works for any purposes without restriction under copyright or database law.
By placing Pixelglyphs, Lil' Glyphs, and the upcoming Invaders! game in the public domain others will be able to build upon the on-chain data which creates each aspect of the projects. New creations are only limited by one's imagination. Each new creation allows more people to become familiar with the original projects.
I believe this will create more value for original Pixelglyph holders given that they own the original artifact from which other artifacts may be created. We have seen great success from projects that are in the public domain. Two examples are Loot and Cryptoadz.