Font matters. It does. I don't care how much you love a certain font, sometimes it is just the wrong choice for your graphic. All fonts have a feeling. They convey a sense within our minds and you want that sense to match your story.
A dark story with murder and mayhem shouldn't have a frilly flowy font and a romance with hearts and flowers and unicorns (because, hey, it's probably out there) shouldn't have a grunge font.
The typography on a cover, or teaser, or ad, can make or break it. Take a look at this example of the simple word 'Always'.
Each of those fonts would be on completely different covers. Trust your designer to know when to use the fancy fonts and when to keep it clean.