As far as the MA Uniform thing--I AGREE- with all of the SD themed people. Since you'll most likely be wearing regular clothes, you better be able to do your stuff in them. However, I wanted to avoid that point of view, as I felt it was obvious.
To me it's not just an SD thing, it's an internalization thing.
My completeness as a musician is somewhat defined by the contexts in which I can express myself musically. If I need a certain context to do music (based on gear, location, style, whatever...) then I'm not as complete. I'm not a 'musician' I am just "a musician when I'm in a place where I can be a musician" and it's as constant growth to become more of a complete musician, to have music be more of who and what I am rather than just something I do.
I've taken the same approach to Martial Arts. Part of my ideal as a martial artist for myself includes how much martial arts if a part of who/what I am. And part of that growth for myself is to expand the contexts in which I can express myself as a martial artists, or at least express the things that make me a martial artist. And a lot of that comes down to clothing, location, and condition. So in my mind, if I can only execute a technique when I am in a certain frame of mind, on a certain surface, or in certain clothes, then that is not yet a technique which I have made a part of me. It's something I can do, but it's not something that helps to define who I am, if you will.
That's a fairly personal interpretation as I don't expect everyone to have the same approach to growth or meaning in what they do so I don't expect everyone to share my opinion, but it's one that does matter to me in how I measure myself and my own journey
So to me, doing a technique in uniform in class is just the first step of making that technique mine. As I expand the contexts in which I can express that technique, I expand my ownership of that technique