"for display purposes" is a correct and usable phrase in written English. You can use it to explain why something is intended for viewing or exhibiting. For example, "The painting was hung in the museum for display purposes.".
They were used for display purposes, and once went to visit Prospect Park.
"I'm sorry, folks, but our love seats are for display purposes only".
I'm sure he considered leaving it on his shelf at the office for display purposes.
They don't even get a green and gold frame for display purposes.
The super hots are reserved purely for display purposes, only to be used in the name of sweaty, painful banter.
(Even the name is for display purposes only; his family call him "Al", after Alexander, his first name).
Though the concept of such a type has challenged recent designers, the face itself is used largely for display purposes, in which continuous reading is not a requirement.
Awesome tool! I started using it one year ago and I never had to look for another app
Ha Thuy Vy
MA of Applied Linguistic, Maquarie University, Australia