The computer on a Starfleet ship is an excellent resource. The database contains star charts, logs of everything that the ship has encountered, and a reference library including literature from hundreds of worlds, historical data spanning thousands of years, and information from dozens of fields of study from astrophysics to microbiology. In addition to the raw storage capacity, the ship’s computer can assist in analyzing data and simulate just about anything given enough data.
While collaborating with the ship’s computer is very helpful, some people do not like talking to a disembodied computer voice. Many Starfleet officers have turned to the holodeck so that the computer has an avatar to communicate through. When Voyager’s EMH needed to learn exobiology, he created a consultant program modeled on an infamous Cardassian doctor. Data consulted with a holographic recreation of Sigmund Freud to help interpret his dreams and Barclay called on the expertise of hologram Einstein to discuss physics and cosmology. Even holoprograms like Vic Fontaine and Leonardo da Vinci would sometimes give advice to the crew in times of need.
Everyone needs advice now and then. When confronted with a problem, why not get the perspective of someone who has been there before? The famous captains of Starfleet have seen it all in their various missions across the galaxy. Their service records, appearances, and personality profiles would all be easily accessible to the computer. What would Captain Kirk make of the Borg? What better way to work through a complicated conundrum than sitting down and enjoying a cup of Earl Grey with a holographic Picard?
Which Starfleet captain would your character most want to receive advice from?