I was out a lot over Christmas and very visible, and I talked in my normal voice to lots of strangers, many of whom had never interacted with a trans person before. I wasn't bothered or self-conscious about it, so neither was anyone else. One guy thanked me - I think he was expecting some sort of militant weirdo and it was eye-opening to meet just a regular person instead. Did that "further the cause"? Probably, and maybe I was vaguely aware of that, but I was mainly just out and about being me and living my life.
Now that all said - I'm very aware that there is a whole set of circumstances that allows me to do things like this. I'm not in a relationship, I have no kids, I'm already out to any family that matter, I'm not going to lose my job if it comes out at work, etc etc. I also have a fairly thick hide, and I still took the best part of 50 years to get to a point where I finally accept myself for who I am. That's possibly the biggest single factor. All of this would have been inconceivable only a year ago.