If you're a sedentary person, and you were to drink 3 of those protein shakes per day you'd end up with 2x your recommended protein intake and only but only 1/2 your recommended calorie intake. That's not a balanced replacement. It's a protein supplement.

Even on keto or no-carb, you still only get 30% of your calories from protein (same ratio as a non-keto diet, BTW). If you were to drink protein shakes all day you'd get 70% of calories from protein. The keto diet does not change the ratio of protein you consume. It only replaces carbs with animal and vegetable fats.

Too much protein is not good for you. It can damage your kidneys. It also causes weight gain, digestive issues, bad breath, and other things.

So again, I say that those shakes are a supplement, not a meal replacement, because they're not balanced. They're great for athletic and active people, because the more active you are the higher your protein requirement is. But a typically sedentary person should not use high-protein shakes as a meal replacement.

A ketogenic or no-carb diet only works if you completely abstain from carbs. If you have one or two keto meals a day, but not every meal, you're not doing a keto diet. Just eating a ton of protein.