to serve a purpose... to?
Some days ago I wrote this comment in a discussion: what purpose serves a piano to a monkey?
I know it is an odd question, but we were joking and I wanted to use a high register to get a comedic effect.
Now, I don't know if it really sounds funny as I intended it to be, but my question is: is the preposition "to" correct?
I only heard the expression used in this context (mostly without preposition):
I hope that my lessons served a purpose in my students' lives.
I don't know why they've added all this information but it probably serves a purpose.
The case that sounds closer to what I wrote seems to be "to serve one's purpose", as in: It often serves his purpose to be vague. (Examples taken from here: https://idioms.thefreedictionary.com/serve+a+purpose ).
I hope my question is clear enough. Thank you in advance!