We have a similar scheme in Sheffield Peace gardens great for kids who don't get a holiday or have never been to the beach.It's the third year and it has grown every year, more rides, more games and more people.
I admire Cardiff Council, they do have good ideas that benefit the people of Cardiff and they are not shortsighted either.
No entry fees, so families can come and enjoy without any required outlay required. The traders don't pay for being there, I believe, so they can see the benefits of growing the event.
Payment is by a token scheme, no cash at the rides. My mate takes his son every year, gives him £20 which buys 20 tokens and then he leaves him to decide what he wants to ride or play, with a strict understanding that there is no top up or extra money coming. So he learns to make good choices and budget.
The event creats a lot of jobs, with the contribution back to the government finances with Income Tax and NI contributions.
The crowds also spend money in the local shops, restaurants, bars and hotels. More jobs created/protected, more tax and NI contributions, businesses survive and/or thrive, generating local contributions with business rates collected by Cardiff Council, rewarding them for their foresight.
It also shows Cardiff and Wales in a good light, possibly increasing tourism and leading to increased growth in other areas.