As an American, some of the quotes from this this BBC News piece five years ago are really interesting: https://www.bbc.co.uk/news/uk-politics-22238582
"Political adverts are - and have always been - banned on British TV and radio. That ban has wide support and has helped sustain the balance of views which is at the heart of British broadcasting - and ensures the political views broadcast into our homes are not determined by those with the deepest pockets."
"The US experience shows the only people who would profit from TV attack ads are moneyed interest groups, TV networks and paid political consultants. The biggest loser would be democratic debate in Britain."
I'm not quite sure how to evaluate those perspectives in light of more recent political events, but still a really fascinating difference in something I've taken for granted as an American.