Humanity has never been so fortunate before. Now expertise is available on all subjects at the click of a mouse. Some may even charge you a buck for their advice. There is no legal definition of “expert” on the internet.
In certain circles it is common to seek expert advice to provide credibility. If it was on a scientific matter, you might ask The Royal Society to look into it. An underling would probably be assigned to put together some evidence which the big cheese might then present as a report. Members of parliament, for example, might not understand how academia works.
If you are a big cheese professor it is likely that you would refer to the wisdom and expertise of other cheeses. In fact, you might have a strong cheese orientation. Say you wanted an opinion on Buddhism then you might try to inquire of a famous Buddhist. The status and provenance might seem to be important if you are a cheese. Obviously high status means greater depth of knowledge.
If you are famous then you can probably get past gatekeepers to talk to high status beings.
A lot of stock can be placed on the say so of experts. People may forget that many experts need to make a buck and burnish their shiny reputation.
If you want to know about someone it is probably best to interact with them yourself, rather than ask another what they are like. But now “referees” are also experts when we are seeking knowledge and the “goods” on someone else.
It is possible for example that someone might ask people who have not spoken with me for a decade or two about what I am like. Yet because they have met me once they might be considered an expert…in the land of the blind the one eyed man is king…