As far as straws go, I agree that for most people in most situations they're unnecessary for most soft drinks. I do, however, think they're a pretty important part of the experience with some cocktails though, it has some effect on how fast you drink it, how it hits your tongue and you experience the flavors, if the drink is layered it effects how those different layers mix, what order you get them in and how the drink evolves as you drink it.

That said, I think most reusable straws make for a bad substitute in a lot of cases because they're too thick compared to the coffee stirrer type straws I usually tend to get in bars when I order a cocktail that calls for a straw. Thinner straws would probably be kind of a pain to clean though.

I'm not a huge fan of metal straws, they're just too hard and kind of unnerving if they crack against your teeth.

I have some bamboo straws I like, and they fit my vibe since I make a lot of tiki drinks at home.