I think yes, it's at the same level as empty($a), but the point is we're letting go of a tiny bit of readability in exchange for a more trusted/clear code. When we do $a === [] we know for sure that it's a plain array and not an Arrayable object or similar. It's down to personal preference anyway.
Lasse Larsen
I do prefer data_get over the array key approach. Mainly because it simplifies the getting, as well as having a default null or value.