Understanding the structural characteristics that make each league unique for betting purposes — parity levels, volatility, home field patterns, promotion/relegation dynamics, and cross-league quality assessment for European competition.
You know which leagues are most and least efficient. You understand that Championship is "monstrously competitive" with massive year-to-year volatility. You know MLS has no pro/rel (enabling tanking) and high parity. You can assess cross-league quality for CL/EL betting. You adjust approach by league.