if no personal reference, and many times its written to be displayed – what is the problem?
yes, people do purchase it. if he doesnt know how to write, he would buy it same as he would buy her a ring.
Chassonim, I sugget you tell your Kalla: “I prefer you do not display it” if thats what you wish.
OTOH, I know a girl who wrote her classmate a nice poem for her engagement, which the couple included in an album of cards, and shared with friends. One bochur, a friend of the chosson was impressed with the depth of midrashim combined (a rarity in our day and age, huh?) and was asking if the writer was a single girl. Today they are a happy couple.
His original interest was created based on her depth, thinking, talent, expression.