One of the primary issues with a run expectancy chart is it takes nothing into account. Or everything, depending on how you look at it.
Thousands of 1st and 2nd, no out situations combined into one number doesn't tell you much. It ignores every iota of context. Who's running, pitching, hitting, playing defense. The score, the inning, the weather. A ground ball machine on the mound with Ryan Jeffers at the plate? The run expectancy is not 1.55. Nor is it 1.55 with the middle of the Yankee lineup due up against, say, Justin Topa.
The end result is, a run expectancy chart sounds informative but Isn't a useful tool to inform strategy.