Yes, it does look natural, but only when done by a qualified dermatologist and when the right dosage and injection technique are used. There are several other factors influencing this as well; the treatment should be tailored according to the need, and overuse might make it look unnatural.
The goal is not to completely freeze the facial expression, but to temporarily reduce excessive muscle activity that may contribute to the formation of dynamic wrinkles.
When the dosage is right, the technique is right, and done by a qualified dermatologist, it shall look natural in most adults. However, overuse or improper administration leads to adults being unable to form expressions properly.
Hence, it is advisable to consult a qualified dermatologist first, who can recommend the right dosage and treatment plan according to your individual facial anatomy and skin concerns.