There are many good other reasons for publishing under a pseudonym or nom de plume. An excellent article produced by the legal firm of Morse Barnes-Brown Pendleton proposes several good reasons for an author to select, use, and protect a pseudonym.
Ultimately, I considered using a pen name to avoid celebrity should my writings become popular. I don't think that it's pretentious to hope for success. I simply wanted, like any good Boy Scout, to be prepared for the unwanted side effects of success.
There are some who seek celebrity. They thrive on it. Yes, they may complain about the paparazzi but they would complain even louder if they stayed away. Personally, I don't understand it. Girls swooning at the feet of crooners. Consumers rushing to purchase whatever product a sports hero is hawking. Citizens idolizing politicians, even corrupt ones. I suppose that I am flawed. I have never felt the urge. I sure as hell don't want anyone ever treating me in this way.
More importantly, I would never want to subject my family to such treatment. One need only look to the travails of the children of the famous: drug addiction, aimlessness, etc.
Ultimately, I decided that a pen name wasn't necessary. I started authoring fiction late in life. I'll be lucky to survive long enough to become any good at it let alone develop any commercial success. My family will be the beneficiaries of any commercial success that may attach to my writings. If such comes to pass, they hopefully will enjoy the income without the notoriety. Well, at least that's the plan.