I'm not saying that the tests should be done with a LiteOn. You're right- in most case you want to see how the burner reads its own products. But there's no reason not to use the quality test. Maybe a Pioneer or NEC won't give you extra data (yet), but you still have the transfer rate.
Used with, say, BenQ/Philips or BTC or NuTech or whatever (in addition to LiteOn of course), you get one or more of PI / PIF / Jitter (maybe even POF). And that is useful information for the person doing the scan at the very least.
Sure, these values aren't absolute and there will be differences from one model to another (and even between drives of a given type- see the c't results of CATS scans for 8x DVD+R media for NEC and Traxdata with identical firmware). But that's no reason to forego this information!
Personally, I will never buy a drive that does not offer additional diagnostics.
G