The government can treat different parts of the country differently as first past the post makes whole swathes of the country electoral deserts for them https://www.independent.co.uk/news/uk/politics/andy-burnham-tier-2-3-lockdown-manchester-london-rishi-sunak-job-support-b1222549.html

When we modelled the 2019 election under STV, nearly every constituency has enough voters to elect at least one MP from the governing party - giving the party skin in the game for every part of the country

When the Towns Fund scandal broke, we spoke about how electoral reforms would mean that the government would have an interest in trying to win the vote of every voter – rather than just the handful of voters that matter now. https://www.electoral-reform.org.uk/paying-the-price-of-first-past-the-post-towns-fund-millions-spent-on-marginal-seats/