That's pretty much the main use of the new syntax. When you have a cascade of regexes, it is even better:

  if m := re.match(...):
     ...
  elif m := re.match(...):
     ...

The world is not coming to an end, as some detractors of the PEP might think. The new syntax is a win in a number of cases. Otherwise, you don't need to use it. The concern for abuse is way overblown. I could live without it (voted -1 on the idea originally) but now that it is in, think it is fine.

Many languages solve that with pattern matching, like in Haskell:

    case f <...> of
        Nothing -> -- Handles the problem values
        Just m -> -- do stuff with m

This is, honestly, much better than an assignment expression. Side-effect expressions always bring problematic cases.

Yep, and common for regular expressions. I’d alwayed liked the simplicity of Perl’s “if ($x =~ /.../) {“ and in Python you had to create the match object before you could test it. Assignment expressions should work nicely there.