Delicate European chives a world away from their Asian namesake
The chives used as a seasoning and garnish in European cuisines are very different from those found commonly in Asia. European chives are thin, delicate and mild in flavour; they're also quite expensive. Asian chives - and there are several types - have a stronger taste and tend to be eaten as a vegetable, rather than something scattered sparingly over a dish to brighten it up.
Chives are long, thin and hollow, and it's the long, thin stem that's consumed primarily, although the pretty flowers that grow on top of the plant are also edible. They have a subtle onion flavour, which isn't surprising as the plant is in the Allium genus family, which also includes onions, garlic and leeks. Unlike the others, though, chives are often consumed raw, because prolonged heat makes them wilt and obliterates their flavour.
Chives are expensive so many cheaper restaurants substitute them with minced spring onion tops. I've been to many restaurants where the advertised "baked potato with sour cream and chives" is actually baked potato with sour cream and spring onion.
Use chives in dishes where the flavour of the other ingredients won't overwhelm them. I use kitchen scissors to snip chives at the last minute and scatter them over blinis with sour cream and salmon caviar, and on polenta with sautéed shrimp.