I don’t know. Is a raw onion as good as a nice caramelised one? Maybe some people think they’re just different. Maybe it’s like coke and pepsi. Maybe they taste no difference at all. Or maybe just with some spices. Maybe some people even like the mix of toasted and non-toasted. Whatever their preference it is because it’s their preference, and so that’s the recipe they hand down to their kids.
I’m just saying you should try the caramelised onion, and don’t just stick to the raw ones because that’s the recipe you know.
I don't believe this is a good analogy. The amount of sugars in an onion is definitely not the same as in a seed of the cilantro plant for example. So the reactants would be different and so would be the product. This is evident by the amount of time needed for cooking, where to caramelize an onion takes a relatively long time. I think toasting spices can vaguely round out flavors, but doesn't really bring about a dramatic change.
Can’t say about others, but with cumin it makes a huge difference.
But, again, we use ground fresh toasted cumin as is, usually sprinkled on the top of dishes. While, regular cumin is cooked with oil/ghee. Cooking toasted cumin will char/burn it.
