I strongly recommend reading Why is CC BY-SA discouraged for code? to understand why Creative Commons does not recommend their licenses for software. In short, the main points are:
The GPL is a copyleft license: it requires downstream redistributors to make available the work's source code ("the preferred form for making modifications," whatever that may be for a given work). CC licenses -- even ShareAlike licenses -- do not require distribution of source code.
CC licenses are not patent-aware, so if a piece of software implements a system covered by an author's patent, a CC license may not necessarily give recipients the right to run that patented system that is implemented in the software. The GPL (like some other software licenses, e.g., the Apache 2 License) explicitly grants patent rights so recipients may run it without fear of infringing an author's patent.
But your question is more broad than that: why is there no "open" license for a given piece of computer data in general? So, we must also consider why the GPL (or even non-copyleft software licenses) may sometimes be unsuitable for non-software works.
For the GPL specifically, copyleft (the requirement to share source code) may be more onus than an artist wants to impose on redistributors. If I share a painting, song, or movie and allow others to modify it, I might not care if they share the underlying editing files with the individual layers/tracks/scenes they used to make a new work.
Attribution also has different practical concerns for different media. It might be really burdensome to distribute a copy of the GPL -- or even a shorter license, like the MIT/X11 -- along with a modified painting or movie. The CC licenses allow much lexically shorter attachments, which may be more appropriate for certain types of works; for instance, CC BY 3(a)(2) says:
You may satisfy the conditions in Section 3(a)(1) in any reasonable manner based on the medium, means, and context in which You Share the Licensed Material. For example, it may be reasonable to satisfy the conditions by providing a URI or hyperlink to a resource that includes the required information.