Aussies and Brits believe they are culturally different until there's an American in the room.
I'm not sure why you think this is worth pointing out, considering that Liberia, Myanmar, and the US are the only countries not using it.
I might be an extreme example, but most people use an imperial-metric melange of some kind.
I hope that wink means you're being sarcastic.[0] Yes, the majority of people are only in a single income tax bracket (20%). And the Pay As You Earn (PAYE) system means that most people who earn wages or salaries don't have to file their taxes. But only looking at income tax doesn't take into account the whole picture. "National Insurance" is effectively just an income tax but it's far more complicated than the income tax system (it doesn't get ring-fenced for pensions or health care or social services, it goes into the same coffers as income tax receipts).
But consumption tax is a VAT, which is notoriously expensive to collect. Then there are tax credits on dividends, and various business tax rules. Oh yeah and property tax is paid by the occupier of a house or apartment, not the owner (council tax)! And then there is the City of London that pretty much gets to write it's own rules.
The UK's tax system is better than some, but it's possible to do _much_ better.
0 - https://www.gov.uk/government/organisations/office-of-tax-si...
I really assure you that the simple implementation of PAYE in France would improve our national gross product by 10%. It is huge, it does mean that way more than 5% of employees, public servants, accountants and consultants are dedicated to write, understand, advise, control and ombudsmaning salary sheets.
Coming from Australia, I am accustomed to multiplying by 52 instead of 12.