An interesting perspective...
I think in a historical context, everybody wearing the identical same clothing had several advantages. Whether a doctor, an administrator, or a farmer, a sewer worker these uniforms, the identical clothing creates a beginning if very shallow, artificial equality.
Make everybody the same and you are equals, brothers, sisters of whatever the training. Dressed differently and the commonality between us is not enforced. Uniforms also allow far greater destruction of clothing. The stuff I normally wear would be stretched, pulled, shredded if it were my standard gear for training sessions. Don;t know about you, but I enjoy wearing clothes I've paid for, as opposed to destroying them anyway?
The belts or sashes can be a very useful tool for training exercises and drills. It can be a practical tool unto itself. To my point earlier, belts remind us though we are like everyone else in the room, that we are the "exact" same, the belt colors are a visible acknowledgement in parallel that we are different at the same time as well. I accept the different belt colors myself as a visual palette for the lessons available to a teacher that class. Rotate teachers, have different classes in multiple locations where I might not know you specifically, the colors are a hint at the fundamental skills available from which to build the lesson... IMHO.
All that being said, I agree entirely with a uniform, that clothing provides an attacker certain advantages solely because of the fiber, strength of the fabric itself. If I do not wear it you cannot choke, jerk, pull, hold me with that jacket in particular.
Like Chen Zen said, we need to practice in regular clothing too, see what that does to our techniques, our mobility among other things. Some daily wear can be highly useful tools as well! But in terms of grappling, the classic judo dogi, the standardized uniform jacket does provide a technical disadvantage provided they can grab us without getting ~destroyed~ on the way in. I would call a tangible disadvantage but minor one.
Merely my opinion, I could surely be mistaken,