"indepdendent" does not mean "i see all parties as absolutely the same".
It means "I am not firmly affiliated". You still have the ability to make choices on who is a better likely outcome
This is correct. That is why I changed from independent to an actual political party. There is no point, it is highly improbable that I would ever vote for the party that is against my values. The two main US political parties are diametrically opposed.
That only matters of you actually do make different choices. But of course in turn even trying to control for that depends on their being meaningful changes in party platforms between elections.
So I'm pretty content calling it a meaningless measure.