I need to disagree, but then I have been schooled and educated on the job mostly by French traders. Hardly anyone ever traded options directionally. And I have worked with guys that pulled in many tens of millions year in year out, buy side and bank prop.
You mean sell-side, right? Most options traders on the buy side are directional traders in one or another way. It's very difficult to generate meaningful amounts of alpha by trading delta-neutral vol, since vol is usually pretty efficiently priced (aside from pure risk premium harvesting). It's especially true in light exotics where the client such as myself is willing to pay whatever vig the exo desk will charge me to get the right risk profile. The idea is almost always that the exo desk will be looking at it from delta-neutral perspective, while I put it on as a directional trade.