odd prep use

[David Bergdahl]

I'm grading final papers and have found a number of subsitutions of
"within" for "in" as in (or within...):

"This role is often seen, especially in these two plays, within the father."

[next 2 by same writer]
"Within the literary works of 20th-century white male authors, one of the
most prominent themes is social difference."
"In the 1950s, Bellow released Seize the Day, "perhaps his finest piece of
fiction," and his short story, "Looking for Mr. Green" was released in 1968
within Mosby's Memoirs and Other Stories.

Is this the case of putting a longer word where a shorter one is subject to
erosion [there's a term for that] or just pseudo-fancy?
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"Practice random acts of intelligence and senseless acts of self-control"