The sites that sit on gov.uk are usually either:

* transactional services - those that let a person do a task, like applying for a driving licence or registering a trademark

* information services - a collection of guidance on a subject, like maximum working hours or data protection responsibilities

There are some that don't really fall into either category and are there to advertise something. They aim to be informational and inspirational. Some examples:

* https://helpforhouseholds.campaign.gov.uk/

* https://www.apprenticeships.gov.uk/

* https://national-security.campaign.gov.uk/

* https://skillsforlife.campaign.gov.uk/

The reason SEO is more important on these is that there's often competition. For example, if I search for 'teach in uk' the Get Into Teaching campaign site will be competing with lots of teacher training colleges and companies, job sites, etc.

Why don't you use SEO on your non-campaign transactional and info sites?

Those are the ones that need protection from fee scammers. It seems you've got it exactly backwards.

SEO is what the scammers use. When Google prioritises an authoritative page, that’s making SEO less important.

No, that's "black hat SEO".

Google has a support article with SEO advice:

https://support.google.com/webmasters/answer/7451184?hl=en/

This. The major risk isn't losing to SEO, it's that the shady operators pay for ads that appear above search results.

Lots of people don't realise they're ads and not the official service.

Google didn't really do much to combat it until the law was changed a year or two ago.