DD just got this email. Is it new? She may or may not do it. Seems odd to ask for it AFTER apps were submitted months ago.
I believe this happened last year as well. http://talk.collegeconfidential.com/grinnell-college/1735229-optional-essay-after-applying.html
My son received the same email. I think they are trying to measure interest. Not sure if he will do it. I think he’s tired of jumping through hoops
I have received the same email as well. I thought I was done with application related work…
Essay complete and thank you email received. It was so short (exactly 99 words) that I could barely get my reasons expressed properly. I would have rather written 500 words…
Having driven over six hours to visit and spend the entire day this past fall, I think it’s much more indicative of demonstrated interest then rehashing, or even reusing, another essay. It continually perturbs me how, particularly as a full ticket paying parent, these kids have to bend over backwards to express their undying love to a college.
^ Not really bending over backwards to most folks considering there was not an essay required in the first place. Hope he struggles through it 
Good Luck and best wishes on the overall admissions process.
Since I started last year’s thread that was linked here, I’ll report back that my D did (begrudgingly) write the essay because Grinnell truly was high on her list and we decided it could only help. She’s now a first year at Grinnell, but who knows if this mattered. She’s met fellow Grinnellians who did not write one. Good luck to all of your in the throes of this process!
Son sent in optional essay. I did not read it
DD did hers.