1. It becomes impossible to avoid taxes.
2. The flow of money through the economy would be easier to trace and examine.
3. Increasing and decreasing the monetary supply becomes trivial to control inflationary or deflationary pressures.
4. money laundering becomes difficult, since every transaction can be scrutinized.

The only useful purpose for crypto is as fiat currency. Whether that’s a good idea is another matter, since it would eliminate transaction privacy.

Since governments are becoming more fascistic, I generally think this is a bad idea, since it would give governments more power (to do good or evil).