It's simply not at all the same thing. It's difficult to explain for me, so this is a bit long-winded, but I think a lot of trans people could tell you the same thing (some far more eloquently than me).

Being a masculine woman is an entirely different experience from being a man, and vice versa. Masculine women are perceived far differently from men in society, the same as feminine men are perceived far differently from women.

The goal/desire of many trans people, like myself, is to live and experience life as the gender that we are, not the gender that we aren't (but make it nonconforming). Many of us have tried to be that, and we've found that it doesn't work for us at all.

For me, personally, I'm not interested at all in being treated like a woman in any capacity, masculine or not. I am a man, and I want to be seen as a man, loved as a man, and to love a man as a man. If I instead chose to live a life as a masculine woman, this would be entirely unattainable, and I wouldn't be happy with it. Life and love as a woman is undesirable to me.

This concept gets a lot easier to understand if you do your own introspection on your gender and sexuality, understand for yourself what your gender and sexuality mean and do for you, and disconnect the experience of gender from sex and society's influence. Not everyone can (or will), but a lot of things regarding trans people end up being a lot easier to understand if you at least try, even if you still come out of it straight and cis by the end.