Getting enough protein is essential when building muscle and staying full longer. The best combination for any snack or meal would be mainly protein, whole grain or vegetable sources of carbs, with a fat that provides clean energy.
You will stay fuller longer if you add protein into the mix, but many times, we often grab snacks that are only carb and fat based.
While I don’t believe you should use protein shakes to get in a post workout meal (that can be done through an actual snack or meal) what protein shakes can be good for is to consume when your other options are sub par.
Many will consume them in replacement for breakfast because the alternative would be to skip that meal.
If you are ever needing to get in some extra protein, you can use shakes as a replacement. You can also use them when the alternative would be skipping a meal or reaching for something out of a vending machine.
I highly recommend Vega brand. They have several different options, but a lower calorie, high protein option would be this one: