Tentatively yes, but with a proviso (see below)
Main Conceit
The ghost story around which the film is based (farmer hears voices, sees ghosts) is on-topic for the site. Aside from the title character, other people such as his daughter and a local author also see the ghosts as well as elements of his fantastical "field of dreams".
On the strength of that, we're led to believe that the ghosts were real, rather than purely imaginary.
Marketing
The film has been marketed as a "magical experience" and a "glowing tribute to all those who dare to dream" but there's no specific indication that the film was intended to be a straight-up fantasy ghost flick. The ghosts are there to further an allegorical tale about believing in oneself, in the face of opposition.
Proviso
We already have an established system for dealing with films that have SFF content, but aren't in themselves fully on-topic
Are works that aren't SF per se, but have occasional SFnal elements on-topic? (e.g. spy movies)
Because the film is an "edge-case", it's acceptable to ask questions about those elements that are definitely (or at least arguably) on-topic or that relate to on-topic elements
"Why did the ghosts pick Kevin Costner's field?" = Fine
"What kind of corn does Kevin Costner's character grow" = Not fine.
