What benefit does an expert get from an introduction?

An introduction gives an expert a broad view of his field, and that can certainly add perspective. By contrast, a beginner won't really understand what's being discussed before he knows the material, and even if he does understand, the introduction will take him captive—he'll believe everything that's written there, and as is well known, introductions always reflect the author's opinion and perspective, while other perspectives are also possible. I'm not talking about an introduction that explains who an Amora is and who a Tanna is, but an introduction to Talmudic analytic learning.