While I sometimes enjoy watching trailers for other films in the "bonuses/special features", when I buy a film (whatever the price), what I want is to watch the film:
I put the disc in the player, I press play a couple of times after I chose the spoken language/subtitles, and then, I watch the film.
Even if you can skip them, I really dislike the sequence of trailers, ads, "FBI WARNINGs", more ads, "enjoy the full experience of ULTRA HD", THX deep note, yet more ads.
They might be fine the first time you watch a DVD, but when, later, you see outdated adverts every. damn. time? That's actually the exact thing that made me abandon DVD's years ago.