W series

Why does w series exist?
In equestrian events its man vs woman with difference being made by the horse.
In motorsport surely its the same with cars replacing horses.
Question 8s are the drivers in a woman only series any good ?
If the answer is yes, then surely the sponsorship money would be better spent changing the male dominated views of the other formulas.
If the answer is no, is it just a case of sponsors going, look I support women but don't think they can cut it on their own.
Use the millions in sponsorship to actually allow female drivers to compete against actual rivals, and then the best of them will get the chance to rise to the top, and then we might actually see some female f1 drivers.