> The advantage of state power is that allows things that are unique to the state to have more influence on policy.
That is also the disadvantage of state power. At least, if you are a person whose life is being controlled by the coercive power of the state government in ways that might be harmful to you.
If you are powerful in the state, of course, it is very good for you to have fewer checks on your own power. It also helps things like arranging elections, like by excluding demographics less likely to vote for you.
As an ongoing exercise it's useful to study over time the number of times the notion of state's rights is invoked in defense of a good idea, a bad idea, or a genuinely disgusting idea. I'm not trying to impose any beliefs on you: feel free to use your own definitions for these things.
My position is that state's rights is invoked so often in defense of bad or disgusting policy in the United States - and frankly, used so infrequently to test genuinely interesting policy in a meaningful way - that it's not a hugely important thing. I feel this is an empirical observation that won't necessarily hold true in all times or places.
When people try to state these things about how government should work purely out of principle, it usually seems pretty unconvincing. We can judge methods of government based on their outcomes to a large extent.
That is also the disadvantage of state power. At least, if you are a person whose life is being controlled by the coercive power of the state government in ways that might be harmful to you.
If you are powerful in the state, of course, it is very good for you to have fewer checks on your own power. It also helps things like arranging elections, like by excluding demographics less likely to vote for you.