Profession is highly situational. Since there is no Profession (adventurer) skill, one can assume that you won't be spending much time actually working in your profession. When you do, it is usually during downtime as an itinerant laborer in an attempt to generate cash. Every profession will have some limited, story-based, practical application from time to time, such as when a character with Profession (sailor) has an adventure at sea. Given the generally optimized-for-adventuring focus shared by most 3E player characters, it's no surprise to me that this skill is usually disregarded. Of the three characters I regularly play, only one has ranks in a profession - the cleric, with Profession (minister) +6. I have yet to have an opportunity to preach to the masses.