The idea of a ready to go FPGA board with working re-usable code/cores/symbols is great and the existing Papilio products represent that well. What this new project does is marry that with the Arduino platform/community and make it even easier to develop with a FPGA. There is nothing wrong with that at all. Adding a real microcontroller with USB frees up quite a bit of the FPGA from running a soft-core like ZPUino while giving extra features like real debugging which isn't available on the Arduino itself.
Saying it isn't all that hard to use FPGAs as a rationale for NOT building a nicely integrated product is funny. It isn't all that hard to use computers either, but I'm guessing you didn't write your own compilers, your own OS from scratch, your own TCP/IP stack, your own web browser etc to get far enough to make your funny post. But datasheets are available. RFCs are available. Reading isn't that hard apparently. I read that somewhere.
Why write your own OS/compilers/protocols/GUI/web browser/blah blah blah when you can re-use well written existing tools and use them to get to the meat of what you want to accomplish. The same is true on the FPGA. Why should some hobbyist with a penchant for authentic C64 audio spend hours learning how to bit-bang code to an FPGA when they could just synthesize a SID core and get to it? Ignoring the fact that there is a whole hell of a lot of work in just "connect the FPGA to your dev board" etc that you're glossing over by making it sound like "just turn the light switch on if you want light, duh!"