Thanks for the thoughtful response. The main reason I replied was because I took issue with your sentence “If trans and nonbinary people didn’t exist, you could, for the most part, look at someone and assume their gender; however, because trans and nonbinary people exist, you can’t look at someone and assume their gender.” I understand that in your particular case, going from the name and photo currently on your Medium profile, you’re unlikely to be misgendered. But that’s not because you’re cisgender; it’s because you’re a cisgender woman and have a traditionally (for the U.S.) feminine name and presentation.
I do see displaying pronouns as an act of allyship for those in your situation. But more importantly, doing so is a challenge to the assumption that a person’s pronouns — or more broadly, gender — can be determined solely from their name. Dismantling this assumption effectively requires cooperation from people of all genders. I hope that makes sense.
As I’m agender myself, I might have a different opinion on this subject from binary trans folks, and either way I don’t presume to speak for the entire trans community on this.