The except method in Illuminate\Database\Eloquent\Builder.php is added to exclude an object of Model or collection of Model in builder query.
Internally, it make use of whereKeyNot() method after extracting the key/keys of object or collection respectively.

Why not modified the whereKeyNot method?
Modifying whereKeyNot() to handle this would complicate its current responsibilities and potentially introduce unexpected behavior for existing consumers. Instead, this PR:

• Keeps whereKeyNot() focused on keys/IDs
• Adds a new expressive method, except(), for working directly with model instances

Usage

Before

$videos = \App\Models\Video::query()
    ->whereIn('id', [2, 4])
    ->get();
$otherVideosUsingWhereKeyNot = \App\Models\Video::query()
    ->whereKeyNot($videos->pluck('id'))
    ->get();

After

$videos = \App\Models\Video::query()
    ->whereIn('id', [2, 4])
    ->get();
$otherVideosUsingExcept = \App\Models\Video::query()
    ->except($videos)
    ->get();