I was in furnature/antique restoration for 12 years before I got into repairing guitars (I worked on a lot of oak pieces.) Probably one of the main reasons oak is not used is that it is a VERY open grain wood. This makes it difficult to get a super smooth high gloss finish. Oak is also very moisture sensitive (this is why oak flooring buckles unless it is sealed properly) and takes many years to cure under a tightly controlled (temp and humidity) situation, otherwise it will crack.