Even if you add Lella Lombardi and Louise Aitkin Walker, that is still not a very long list for the past 45 years.
Vanina Ickx, Claudia Hurtgen, Jamie Chadwick, there's a whole bunch of others I've missed. Still not many for 45 years, but there's been women in top-level sportscar racing at least for decades. Drivers are not the stars in sportscars, so they don't get as much exposure.
Like other sports (e.g. football and cycling), if by having a female only competition it increases the awareness of and participation of women in motor racing, then surely that is a good thing. And hopefully it will result in a longer list of women competing in major competitions in the next 45 years.
The ones you suggested are athletic sports, where there often *is* a measurable difference ( although honestly I don't think there's a huge difference in football - the main problem there might be simple infrastructure ), This event smacks of marketing - throw all the cash it takes to run it into basic level exposure ( reduced price karting events with people there to talk about motorsport careers, for instance ) and then you might get something *actually* happening. Every woman I've talked to about this idea has been either dismissive of it or actually annoyed - if I was a driver I'd probably appreciate the relatively low competition for the prize, I guess.