I disagree.
If it gets you in the correct mindset, then it's worthwhile. A normal t-shirt and shorts might not encourage you to push harder, but wearing the 'correct' gear might well make you beat that PB or go the extra mile, literally. For a lot of cyclists, especially those at club level who do take part in proper events but who aren't pro, it's no different from the people on trackdays who wear the proper gear instead of jeans and a t-shirt. If you can afford the best, then why not? No harm in it.