Then they understood how Bitcoin is money no matter what others might say. They stopped seeing it as some geek weird thing. I think using Bitcoin in real life in return of some useful service in front of clueless guys that still think it's not real money, is a great way to teach them how Bitcoin is very real and the real party hasn't even begun yet. Thats why we must never forget about the importance of small transactions like those. Buying some coffee in exchange of Bitcoin impressed them more than any of the revolutionary protocol tech stuff you could explain them.