An essential difference between cat and print is the class of the object they return. This difference has practical consequences for what you can do with the returned object.

print returns a character vector:

> print(paste("a", 100* 1:3))

 "a 100" "a 200" "a 300"

> class(print(paste("a", 100* 1:3)))

"a 100" "a 200" "a 300"

 "character"

cat returns an object of class NULL:

> cat(paste("a", 100* 1:3))

a 100 a 200 a 300

> class(cat(paste("a", 100* 1:3)))

a 100 a 200 a 300

"NULL"