True, however, it all depends on your intent. If you are not planning on watching blu-ray movies on the go often, then you would likely want to buy the desktop drive.
Its the same issue with me and lightscribe. I can get a BenQ $50 lightscribe drive for my old desktop or I can pay double that to get one for my laptop. This was just an example, however, as I dont think lightscribe is worth the money at all and certainly not worth paying extra to use on the go. I actually do own the BenQ DW1655 though.
Personally, I hardly ever use my dvd drive and especially not on the go, but I cannot take it out in favor of a second HD since its a slot-loader and its cool to use.
Anyway, to finish my ramble, I'll just say that once they offer a slot loading blu-ray drive that fits the chassis, I'll be all over it.