is the word transgender necessary for everyday, practical usage? From my new understanding, it's just another way to describe gender expression.

It isn't, and neither is "gender expression".

Words should describe distinct concepts which actually exist as distinct concepts. There's no such thing as universal "gender expression" and therefore no such thing as transgender.

In 2020, the gender rebels are: * homemaking husbands whose wives earn money in the formal economy * anti-hijab protestors * people in homosexual relationships.

These groups and their standing in the world are very, very different. However, all of them would be offended both by the suggestion they aren't really their actual sex, or that their defiance of gender norms should form the basis of their personality, or that these fundamental, life-changing decisions happen to be or should be accompanied by adopting a number of superficial mannerisms commonly associated with the opposite sex. Like, if you've gone so far as to risk your life to defy conventional femininity, a double mastectomy is a minor thing and pronouns don't even register on this scale. But this isn't happening, of course. Because gender isn't a spectrum, it's garbage.

Now people who modify their bodies after the oppoiste sex exist, and they deserve the same rights as other body modification enthusiasts. A "transwoman" no more belongs with women than a transcrocodile belongs in the swamp with the other crocodiles.