It's all part of his cleverly crafted persona. Just like him using his middle name. The average Brit doesn't know that the real man is Alexander Boris de Pfeffel Johnson, who used to burn £50 notes in front of homeless people for fun.
Remember this guy wanted to invade the Netherlands.
This time it's the US that's 4 years behind. You have your own Dominic Cummings and everything.
Only the Jubilee line has them here in London. They're a good feature. There was talk of bringing them to other lines, but I've not heard any update on that in years.