To each his/her own.
I get all I need from a poster, synopsis, stills,... and it's what works best for me.
Trailers are a helpful thing.
Time and money are important commodities.
It's good to know something's worth it before you part with either.
And you never been duped by a trailer, resulting in a loss of money and time?
I've been fooled too much times to trust them anymore