You are right, Stella. If it is your own bike, you learn about its individual characteristics, how to use or overcome them and how to look after it You will have to buy your own and pay for its upkeep and repairs at some stage.
In the long term, the best riders are those who know the bike well, who can report back on problems, and, fronkly, those who have worked hard to get where they are....Joey?
There is a danger that in these series where the bike is supplied, Dad, or some other person, will pay up, for a rider with less ability, and, crucially, less committment.
It is part of the best personality and character for racing, to tackle a challenge head on...running your own bike is just that.