A study was done a number of years ago by a midwest US university when butchers were told by Health Authorities to stop using wood and start using plastic boards. Wooden boards have a natural antimicrobial property that plastic boards don`t have and there is some doubt as to which is the healthier choice. Woods high in tannin have greater microbial resistance but most woods have some. I don`t know if using an oil treatment on them tends to defeat this process or not but as I said the oil doesn`t really accomplish much in my opinion. Someone suggested that it helps keep the wood from warping but if you only wipe them down then the amount of water absorbed is going to be fairly minimal and should dry quickly.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.