I fully agree. The black economy, tax evasion, benefit fraud, CMS fraud, modern slavery, money laundering, etc all needs a massive clampdown and a compulsory ID card system is essential and central to that.
Far too many people have more than one identity - bank accounts in different names - not from forged/fraud ID documents obtained from criminality, but just legacy from when things were a lot more lax and banks weren't required to check ID quite so thoroughly, or even two identities after changing their name by deed poll or marriage and keeping certain things in their previous name. It's a lot more common than people think but prevents authorities like HMRC being able to cross check official databases properly. (Handy for those indulging in evasion/fraud and other criminality).
Then you have the "look a likes" - people taking driving tests for relatives, people sharing driving licences and giving false details when stopped by police for driving offences - getting a relative to attend the police station within the 7 day "production" period and the desk clerk not having any way of knowing if the person in front of them was the person stopped by police!
I think it's part of why HMRC, local councils, police, etc don't show much interest with the Turkish barbers, hand car washes, sunday markets, etc - the people involved aren't obliged by law to have identity documents with them, and will probably not turn up at court if summoned, so if the police can't arrest them at the time (either because they're not arrestible offences or no spare cells in the station), they're powerless to take action so it's just a waste of time.
That's why the "joint" operations like road stops, are more successful, but pretty rare, where you have a big attendance from all the different authorities, i.e. police, HMRC, council, border force, DVLA, etc., and those stopped are checked over by all the different authorities, and there being vans for taking away suspects, recover trucks to remove seized vehicles, holding cells available in police stations, etc., all ready and waiting, i.e. all the ducks in a row. Likewise with checks on "dodgy" takeaways where "slaves" are living on the floor above the shop, etc. If we had compulsory ID cards, we wouldn't need such labour intensive joint task forces just to try to identify someone, check their immigration status, check criminal record, check right to work, check tax records up to date, etc. - all could be done linked to the ID card.