Lexis briefs are extremely short and useless for law school purposes. They are for researchers who don't have time to read the whole case.
I disagree with your disagreement. Lexis is good for a quick overview, but the canned briefs have several advantages including pulling out the procedural posture, and, if they're for the casebook you're using, focusing on what the casebook focuses on since the case in the book is generally edited to a snippet of its former self.For example, a case on a wide range of topics might appear in a Civ Pro book, edited to show how FRCP have affected the case/outcome. The Lexis brief might focus on substance and gloss over or skip the procedure. The brief for a Civ Pro casebook would give the relevant procedural info.