The clothes, manners, and rituals are key elements to Aikido as a culture and not a technology. Whether or not you believe Osensei cared about transmitting Aikido as a culture, I would still argue that these things are important for non-Japanese because we can't just take these elements for granted.
BJJ I believe uses competitions to foster a culture, but it is an emergent culture, a thing that comes about.
There's nothing wrong with studying the culture, I think that's important.
If I studied the culture of Rome (as many people do), I might try on a toga to experience what it's like (as many people also do). On the other hand, if I wore a toga on a daily basis while conducting my studies it would just be...odd, wouldn't it?