^Not the same thing. We read or watch series fiction for its characters and storylines. The ship is just a setting. There are Sherlock Holmes stories set during times when Holmes wasn't residing at 221B Baker Street, but that doesn't make them any less Sherlock Holmes stories, because they still featured the main characters.
who gives the books their tittles.
Besides its kind of hard to claim the characters are that big in making something a Star Trek book, when a TOS changed the cast three times.
Plus the characters and storylines argument also falls apart when you remember TNG didn't have the TOS cast, DS9 only had two TNG characters, VOY didn't have the TNG or DS9 cast, and ENT didn't have the VOY, TNG, or DS9 casts and yet their still considered Star Trek.