Spiney
Flew in La for over a year and can add the following. Yes, the Route Chart is great for landmark references with diagrams depicting landmarks, commonly used for, though not required as, reporting points.
Down side is the size of the chart and ease of use in the cockpit and lack or topographical terrain info (unlike the Terminal Chart).
Practically speaking, which i gather is the jist of your post though, many commercial operators fly point-to-point in the LA basin, ENG certainly do and most corporate also, no triangular routes flollowinging freeways when a straight line will do is the rule. That said, instructors and students tend to follow the highways when training and transitioning pilots less familiar with the area.
So its a mixed bag of how does and doesnt follow the "routes". In LA when outside controlled airspace, helis give position/altitude/direction reports on air-to-air 123.025
ENG Brit