To rephrase what you suggest: personal recommendation is the dominant driving force in choosing a travel destination. My refinement is that the influence of these personal recommendations is often conditioned by the trust and relevance of the shared experience.
A friend may praise a destination, but if their interests do not match yours, the impact is less.
Travel guides, on the other hand, offer a structured overview that allows adapting information to one's own preferences.
For example, if your friend only swears by seaside resorts but you seek cultural authenticity, their testimony may be less useful than a guide describing traditional villages or historical sites.