Apple extended C with block closures years ago.

  int b = 0;

  ^(int a) {
    return a*b;
  }

The declaration for lambda variables is almost identical to function pointers, just with a ^ instead of a *, so there's nothing to learn (or unlearn, like C++ forces you to). The ^ looks like a lambda, and historically the lambda of lambda calculus actually was a caret accent over the variable. The argument list can be elided.

I honestly would have much preferred they had a keyword so that it kinda matched the rest of the language. It feels a bit tacked on and hard to parse.

Something like:

lambda(arguments):capture list {...}

Just seems way more clear. Looks more like a function or a class (and a lambda is sort of an in-between kind of thing anyway)