I'm not sure why you seem fixated on branding it as 'showing off' - I mean is the singer showing off when he sings? Is Usain Bolt showing off his speed when he runs the 100m, which is a competition to see how fast you get from A to B? You can always ask, "What's the point of this" regarding any sport, art form or pretty much anything, and often it will boil down to: someone's put a lot of effort into what has grown to be a passion of his/hers, and then shows it to other people, often for money. It has no meaning. If you want to call that 'showing off', that's fine, but it implies negative connotations which in turn devalue the work put in to the performance/result as trivial, or not worth anyone's time.
If people were to take that approach for cardistry videos, which this could be described as (or could it? only 5 clips show actual cardistry moves, the rest are classic flourishes magicians use) , then others would have little to answer when someone, instead of commenting on how the actual content of the video could be improved, criticises its entirety by brushing it off as 'showing off'. If you were to post a video on a performance, cardistry, general magic theory or what have you, I wouldn't question the 'point' of it, rather assess how well you achieved what you set out to achieve in that context.
When I say 'plays a lot better' and 'grabs attention' I mean exclusively in the context of videos, especially amateur-made ones. Cardistry and colour changes on their own aren't going to play better in person, for many reasons, compared to performances of an effect wrapped in patter and misdirection; however they will on video, for the simple reason that you get the 'wow's or 'kicker's straight away, in quick succession. Misdirection on video when filming for the camera is much more difficult, freedom of movement is limited. I don't think I need to do some research to ascertain that to be true. When full performance videos become extremely popular, this is almost always due to the fact that this person is either a famous professional, or has built up some other kind of following that will watch whatever he puts out, like youtube subscribers.
In conclusion, the strength of color changes and flourishing on video is that many different changes and cuts can be packed into a short amount of time, so that there will be something for almost everyone to stop and think: I really enjoyed that part. Videos of performances for other people will only be enjoyed by magicians, as you get a 'side view' of the performance lacking misdirection and often cover for moves; and performances for camera are limited to either one trick per short video, or an extremely long video if you want more than one.
As for clothing, point gladly taken, a more appropriate sartorial choice will be made when my friend and I decide to fiddle on camera some more
