Good for A-spec points too. At least to see how many you can rack up. I was using my 190hp 'Spirits MR-S' on El Capitan, and won easily on level 10 against some 400hp+ cars. It was fun.
I find it a good way to learn it as a short competition is better than driving in an empty track.
And choosing your opponents level is a good option (but choosing each f them would have been better)
I used it to rack up B-Spec points because you can set the AI difficulty. I set it to -10 to begin with and just ran races with a variety of cars and tracks. The more machine/course/battle points I got, the harder the races became to the point where B-Spec Bella can now easily win a race with a difficulty of +10.
A lot of people have named their B-Spec driver B-Spec Bob.
However, my B-Spec driver is female (not to sound sexist or anything but a woman in a racing suit ...) so I named her Bella. True, I could have used "Belinda" or "Betty", but "Bella" sounds the most exotic.