In the UK, no there is no need, BUT many want to go on holiday this year, maybe Spain, maybe USA, maybe New Zealand, so at least for this year, the thought of a 'passport' seems the logical thing, by next year everyone will know how good or bad the vaccines were, and the 'pandemic fear' factor will have subsided..I hope !
Most people have a passport or a driving licence, which has been said you do not have to carry, although it's easier if you do, get stopped, and you still have to trudge to a Police Stn within 7 days to show it ! (Licence not PP).