I just thought of this, and I want you to view it from your own perspective. As everyone hopes that more people get to believe and use bitcoins, I think bitcoins can gain more new users on a large scale if anyone (whales ) can place their advert through a popular football club just as some companies do sponsor football league. I think this will send a strong message to billions of people across the world who do know but does not embrace Bitcoin usage.
Let me site another example, let's take for instance, a club announces that they will pay their players in BTC. This news can also help people adopt BTC.
I guess a lot of bitcoin enthusiasts have done it before but still they end up only with bitcoin popularity, not in bitcoin global promotion. That’s why a lot have settled only in bitcoin as an investment tool. However, if you want to try it for yourself, I’d still think that’s a great idea. But make sure that you know the risk first of using bitcoin as a currency so that other people won’t blame you if their bitcoin prices have suddenly experienced price decline.