Well, the MSP series of chippery is hardly a fully fledged multimedia CPU, the model they chose has 128KB of flash and 10K of RAM.
Assuming they they want to flash the the firmware on the micro itself, it's not such a bad choice, it's reasonably cheap at USD4 considering what they want to achieve.
Yes, they could've done it even cheaper with a separate flash chip, and an even cheaper micro but you have to wonder if will actually work out cheaper consider the extra board complexity.