I've never been convinced that L-L and R-R match-ups are worthwhile for pitchers; same for l-R and R-L matchups for hitters. Good hitters get a hit and good pitchers get an out.
Yes, there might be a small difference over a long sample, for for one batter it is worthless, or harmful. I watched Billy Martin who, aside from being drunk too often, had an obsession with maneuvering his lineup to get "the right match-up".
What's the most reliable stat? A good hitter fails 70% of the time; the greatest modern hitter failed 60% of the time (Ted Willimas in 1941, I mean) in his greatest year.