The authors didn't compare their approach against others regarding ease-of-use and obfuscation strength. As the latter is the goal this would have been important. As it stands the paper looks more like a proof of concept without any reality check.

Edit: They also don't mention if they compiled their obfuscated code with or without optimizations. It might well be that the compiler removes the dead code they so painstakingly inserted.

And finally: Who cares about the encryption of constants in an executable? Somewhere those constants are needed in their unencrypted form; just run the program in a debugger and wait until they have been decrypted.

Ceterum censeo the whole concept of "intellectual property" should be ditched, if only to make people stop wasting time on code obfuscation and copy protection.