In my examples, the backlight is generally not any closer than the front light. Regardless, now I understand what you're talking about. The backlight actually has to cut through the front lighting to make a difference, while the front light merely needs to illuminate.
Washes provide a softer/diffused light, while we want a hard-edged beam of focused lighting for our spots, which need to cut through pretty much everything.
As people should be able to see, lighting can be quite the art form. Even more so in film and television where the lighting can make or break things. Anything learned in one aspect of lighting can be applied in other areas. GOOD knowledge of TV/movie/film lighting can definately be applied to stage lighting. Stage lighting guys I would suspect would need some additional training and practice to get TV/film lighting right, while the TV/film folks would need to learn to cut it back a few degrees UNLESS doing a video shoot.
Sometimes I just need a more real-world and relatable example to grasp it. That definately did it for me.