I think it's very helpful too. All scales in western music can be related to the major scale. It's the Rosetta Stone of music. Knowing that the natural minor is related to the major, hence the name "relative minor" is an obvious example. If you want to know what a minor chord progression is as related to the major scale, you just add "2" to the roman numerals. Kindergarten math... And that's why they call it "relative'.
Melodic Minor is simply the Dorian mode with a major 7th. Easy.
Harmonic minor is simply the Aeolian mode with a major 7th. Easy.
There's no need to make any of this stuff hard. It's not.
Thrill is Gone is: "i-iv-i-VI-V-i" in B minor. The V would normally be "v", but it's a secondary dominant here I guess. I never really thought about it. But, I feel it's ok (and necessary) to be precise in your thinking and writing. It's the lack of precision when explaining music to people with no real musical background that causes problems. So when you tell someone a minor pentatonic is 1-3-4-5-7 it's incorrect because it implies a natural 3rd and 7th. Luckily someone caught it. If you're gonna explain something at least be right. Steering clear of "technical jargon" means your' just gonna explain it wrong. So in the future when someone tries to match up your info with the real world, it's gonna cause some confusion. Just learn stuff the right way the first time and be done with it.
Anyway... The whole trick is, you need to really understand the major scale, in all its permutations. That's where most people fall over, because they think it's so easy that it's not important. Or usually, it's that they don't understand how to manipulate the major (and consequently every other) scale. They think it's just something you go up and down with, one note after the other. If the fundamental understanding of the awesome major scale is weak, the flaws carry through in the understanding of all other scales.