One of my best friends is a trans woman. She saw her mother grieve her lost son. She said to her mother, "will you help me select my new name?" Her mother was very proud of her daughter, and they decided to find first and middle names with the same initials as the birth names. Although my opinion doesn't matter much, this has always seemed a way, a very small way, to link the past to the present. Some people, of course, do not want a link to the past, and that is their choice.

We do not use the term you are discussing, she hates it. I am sure, since trans people are no more monolithic than any other group, that how trans people feel about this varies greatly. I am just an ally, and I cannot, and will not, ask anyone what their name "used to be" . As my Dad often said, IINMGDB!