You are correct in some instances. The construct of gender is for a lot of us just used as a tool. Some of the time it's to alert people to how we wish to be treated... Which is the passable but non-ideal win. It's not the fault of people's brains encoding us to a binary standard that is keyed to read our characteristics as vital information. At some level we are animals and our brains treat info about sex as important. I have friends I know are trying their damnedest to respect my mental health by using language and means of cultural inclusion which don't hurt but a lot of them slip because their brain isn't naturally processing me into the correct category. They are looking out for me and trying ... but the switch obviously hasn't flipped.

When the switch does flip and you are properly read people legitimately treat you differently. It feels so bloody natural and fast like you are used to dealing with lag and all of a sudden you are on a fast newly formatted machine not bogged down by bloatware. Moreover a lot of things stop feeling artificial and like someone trying to calculate how they are supposed treat you. Getting that switch to flip is aided by social constructs - gender expression which the brain learns to read as just more markers of sex. It's the extra power to get us over that hurdle.

It's imperfect though. To use gender constraints as a tool can get you what you need but sometimes at the cost of what you want. The number of transfemmes out there envying the cis girl wearing the low effort androgynous shlumpy t-shirt and jeans and still effortlessly getting correctly gendered when they go out to do stupid bullshit errands... Is like the trans Cinderella wish.... Most of the trans femmes I know are one " Oh fairy godsmother I wish I could go to the 7-11 without eyeliner and not have the cashier call me "sir"." away from selling their souls to the fae.

On the flip side Try being a pre-T flamboyantly gay transmasc with not uber straight masculine vibes... You can perform like a puppet on a string to a rather stupid and arbitrary social convention of rigid gender performance or you can have people hammer on your feel like lukewarm invisible crap button all day making every social interaction you have feel like an exercise of utter pain as your dopamine rapidly flees your body and leaves you an empty husk.

Most of the time you kind of have to pick one. We are slaves to the construct cage of gender more than most. What is underneath it all is something we do not wholly control. What I experience daily makes no logical sense from the idea of gender always being a choice. I can learn how I work but not change it... Furthermore if it were something I could change I don't think I would. It would be far greater violation of selfhood to change something that has colored every relationship with myself and every human being I have ever known just so I could be comfortable in a body I don't like.

The categories that encompass "man" or "woman" or whatever are socially constructed. The outlines of those categories especially are so far from being absolutes of nature or physical constants.

But people still have an innate sense of themselves and their own identity. So even though the rules are made up and the points don't matter, people can still know which box they go in based on that sense.

For some people, they're just comfortable in the box everyone right they'd go in and never think about it. Stone people don't care which box they're in and so never bother to think about it. There's all our cis folks. Stone people don't really care which box they're in, but they do still think about it and decide they go outside any of them. Some people think they go in one box sometimes and either box at other times. There's the nonbinary folks. And then there's people who can tell they fit in a box, but everyone seemed to think they're actually in the other one until they mistake was pointed out.

The boxes themselves are totally made up, but they still exist. And since they exist, people can still tell which ones they go to. The fact that the boxes are fake doesn't make them not "real", it just makes enforcing them and telling people you know what big they should be on better than they do stupid.