Earlier quoted context omitted.
Why thankfully?
Because syntax actually does matter, and Lisp is only a local maximum. Thinking otherwise causes pain, as people try to use Lisp in situations where it is not the best answer, and is therefore harder to use than other languages. So, "thankfully", because acknowledging reality here means not having to live with the pain of using a language that is sub-optimal for the problem you're working on.
Put another way, do you have evidence that it is important? Has it let people write better programs? How would you prove that?
This is akin to saying grammar is important. It is, to an extent; but over adherence to grammar is usually not an effective way to communicate.