A Bitcoin advertisement would be great, as it exposes BTC to a broader audience. There are a few billboard ads, which were already shared. We shouldn't forget, that at this year's Super Bowl advertisement session included an ad referring to the Bitcoin futures:
https://www.financemagnates.com/cryptocurrency/news/bitcoin-goes-super-crypto-firms-storm-super-bowl-advertisement-stage/

To quote Henry Ford:
"A man who stops advertising to save money is like a man who stops a clock to save time."