That said, I never understood why a ship's counselor spent so much time on the bridge. Didn't Troi have officer hours to see clients? If Picard needed her on the bridge to provide empathic insights about the odd alien, he could summon her.
Probably the same reason the most experienced and least expendable members of the crew were always the ones to visit alien planets, crawl into dangerous ducts, and so on, instead of having away team characters and so on: the TV producers wanted to focus on seven characters and keep them in the spotlight as much as possible.