It doesn't diminish their value, but it takes away from the magic and showmanship behind the whole event.

Exactly, I think you're just describing marketing, which some would view as a form of dishonesty or at least smoke and mirrors.

I hate dishonest marketing as much as the next person but I don't think it's a stretch to say that there is nothing wrong with telling a good story about a product. And of course, telling that story means de-emphasizing unpleasant tradeoffs, and emphasizing pleasant ones. The ultimate concise version of this would be a list of features. That wouldn't be nearly as exciting or informative, would it? (I recognize that you did not personally advocate the position you relayed)

Honest marketing is explaining the value of a product. Marketing can be smoke and mirrors, but to deny its utility is shortsighted.

This is a fantastic point. Marketing isn't evil - it's just a tool. It gets you connected with things you want faster. And like anything it can be misused.

I think in most cases marketing deprives me of things I want faster being a resource hog.

That's advertising. Some consider it a subset of marketing. Some consider it an entirely separate area. I agree. Ads on web pages are resource hogs. ;)

In its purest form, marketing is any communication from a company. Without marketing you would not know about any products from any company. So some forms of marketing are very valuable to everyone. As with any discipline there are bad points as well.

It's no different than show or movie spoilers. Do they make the show less enjoyable? Does that reflect on the production quality?

People enjoy the keynotes for the suspense and shared joy and excitement.

Leakers of movies, shows or new device features do take away some joy from some people. For me, the fact that 99% of the features are available in some form on another phone already (unlike early iPhones) is a bigger spoiler than the leaks.

I love seeing how Apple can take existing common features and take them to 11 and it's why I've come back to iPhone.

these events (and many other things like unboxing the product) are a big part of the experience that apple wants. not everyone like it, not everyone cares about that side of things (and that's ok!), but for those who like these experiences, a leak is just like someone spoiling what happens in a movie.

I'm not so sure about that. Even though the iPhone 4 got HARD leaked, it was still such a diverge from the competition when Steve and Co keynoted it.

All of the X leaks had me wondering "I hope they have more to this because this is effectively a S8;" the keynote didn't change my opinion.