Also disagree with

  > 6.2 Watching Functions
  >
  > Another common problem is the utilization of functions
  > in watchers or bindings. Never bind anything (ng-show,
  > ng-repeat, etc.) directly to a function. Never watch
  > a function result directly. This function will run on
  > every digest cycle, possibly slowing your application
  > to a crawl. 

A while ago this sort of advice was true (when you'd see people inlining stuff in `eval` to avoid this), but nowadays function execution itself is very fast.

You don't want to watch a slow function, but just watching a function will not "[slow] your application to a crawl."

Interesting post, but I'd take this author's advice with some salt.