If Seeed would have GPL-licensed their original open-source code, we would not had all these different closed-source derivatives… Of course, for many end-users, a nicely working closed binary is more important than having the source code. But over time, I think open-source (with proper copyright and licensing) pays off for everybody.
EDIT: I checked the source code, and it is copyrighted to e-Design Co.,Ltd. I do not know if they anywhere have allowed other people to copy, modify it and redistribute (binary or source) derivative works.
EDIT2: There is a MIT license on code.google.com/p/dsonano/ so if the code is taken from there I guess it is licensed under those conditions. You basically have to distribute the license together with your version of the software.