Near the end, when they get to the mountain and are looking for where the door is, Biblo looks up and points it out for them.
Thorin then says: "You have keen eyesight, Master Baggins".
Huh? Keen eyesight? There is literally a giant statue with a staircase you can see clear as day, on the side of the mountain.....Yes, keen eyesight indeed.
True but none of them dwarves payed much attention at the statue or the hidden stairway. Bilbo did, he doesnt quit easily, he stayed back even after they gave up. His curious eyes would force him to look for answers, he also found the keyhole. See? He's a curious hobbit.
On the other hand, dwarves have evolved (or been created) to live mostly underground and to work at crafts - mining, metalworking, gem-cutting, enamelling - that call for close-up handwork. It's possible that they have lousy distance vision, since their environmental niche just doesn't require it, and that Bilbo really is the only person there to whom it's more than just a lump of something blurry in the distance.
There are those Filipino nomadic boat people who dive for sustenance, and they say they can focus underwater when most of us can't because they start diving when they're little and their eyes develop in a certain shape, whereas when humans in general reach a certain age it's too late for their eyes to make that adaption.
Although at the same time, that would make their massive underground halls kind of redundant. What's the point of all that grand sweeping architecture if they can't focus on one side of one of their halls while standing on the other.
Also, when watching a movie I use a bit of imagination and allow for the movie to show me things that the characters can't see clearly. If we were shown the statue from the distance that the dwarves couldn't see it and only one with keen vision could just see it, we would have been disappointed with the shot.
This phrase is from the book, but I cannot remember when and how many times Thorin said that to Bilbo. I remember that he trusted his eyesight when they are crossing the enchanted stream in Mirkwood. Secondly, it is Bilbo who finds the door also in the book and exactly finding first the stairs that are obvious exactly like Columbus's egg as is said in Spain: when somebody shows something then everybody thinks how easy is to find it. ;)