ZPETypes were first introduced to ZPE a few years back when the move to 'everything as a function or object' concept evolved. This paradigm shift made it impossible for ZPE to encounter data types such as BufferedImages as it had previously, restricting such data only to ZPE structures (and, indeed, ZPEObject instances). This tidied up the core of ZPE, improved performance, and caused fewer crashes.
Now, I embark upon perhaps the most exciting yet ambitious project in ZPE's history: shifting away from generic values to ZPETypes for all return values. This is not going to be a quick job either, and it could take several days of development. But it's necessary to make ZPE feel more solid and improve performance even further.
ZPE is close to its 100,000th download as of this year, so it is time for this change to come around. I seek to have it done by the end of the summer.