If you have more than 10 ras boys you’re playing pretty bad. Mass fab grids are better for scaling after t2 mass fab rings. You make boys for the bp and the small eco boost that can ideally be used for further mass fabs until you reach game ender stage.
They aren’t essential and can be replaced with t3 engies. You got a better argument for demanding aeon and phim getting engie stations than RAS SCUs for phim, frankly.