[Closed] This scrappage scheme - is it just a con?

I am currently looking to change our 11 year old Mazda 3 (owned since new but really beginning to sag) and am looking at options. I got a price from CarWow on a new Seat Ibiza and I can get £2,500 'saving' on new if I buy outright.

However if they take the car they will give us £2,500 as 'scrappage' but they won't discount the new price so either way the new car would cost us £12,000.

So what is the point of the scheme as there is no incentive - if I don't trade it in I can sell it on (probably get around £1,200 for it) and it will continue to pollute which surely goes completely against the point of the scheme?