Between Brexit and Covid I've read that the UK's population might have dropped by more than 1 million in 2020 [1]. For the time being, because of Brexit, it is also very touchy politically to do anything that might resemble free movement or easy migration with the EU. So if I were a little cynical I might say that this is a way of encouraging immigration without looking like it and it is actually a popular policy within the Conservative Party [2] (and probably the public at large). Two birds with one stone.
There's also quite a bit of arguments within the government about the stance to take on China so this can also be a way to placate some MPs so that they stop pushing for more serious measures.
[1] https://www.telegraph.co.uk/business/2021/01/14/uk-populatio...
[2] https://www.conservativehome.com/thetorydiary/2020/06/our-su...