Britain to introduce compulsory digital ID for workers

So I currently have;

A National Insurance Card (needed to get a job), drivers license and passport, one of latter is also needed (in practice) to get a job.

Why would a brit card help us reduce the number of people working illegally?

The only notable 'employers' of illegal workers in the UK are American tech firms Uber and deliveroo (doordash) because they allow driver substitution without verifying that the substitute is legit. That should be made illegal and then fine them into the ground for anyone who slips through. Brit card doesn't help and is a distraction.

A Brit can pass a RTW check without a drivers license or a passport - a paper birth certificate is also acceptable (and paper can be lost, damaged, forged), as neither a drivers license or a passport a mandatory. Getting those can be expensive for some people while this ID is free.

A NI number is not ID, it's a reporting number.

Lastly, a national ID is a tried and tested scheme in many, many countries and brings a lot of positives. The only "negatives" are slippery slope make-believe scenarios not based in reality.

https://www.gov.uk/prove-right-to-work

I appreciate that, I decided to exclude it for simplicity because obviously not everyone working here was born here :)

I don't really understand why I need a Fourth (or Fifth)! National ID?

I don't really get the point on reporting number, true, but it's also a UID linked to a passport or birth certificate.