Using a persona is something many people do. The reason that we do this is in order to protect the sensitivity of our psychological space. This means that the private thoughts that we have will not be disrupted by the intentions of those around us, because we are in essence creating some type of "sandbox" within which we are free to explore without having to deal with the questions and norms and expectations of society.
Maintaining persona is important at all stages of life. But it's most important role is when we are at the initiation of a new identity. During the developmental phase, for example a teen living within the context of nuclear family, creating persona allows us to isolate development from the baggage of our immediate stake holders. However as one grows older, or rather, chooses to accept responsibility for the development of others rather than just the self, then the persona becomes a hindrance.
It becomes a hindrance because we are only able to guide psychological development based on the inputs we open ourselves up to. Having a persona protects us, but also keeps out information that is capable of further developing or maturing our thinking. Within the persona we are safe to experiment, yet the raw material we have available to use also becomes limited.
So, persona is something useful throughout our life when we are incubating our world view from those closest to us, but then can stand in the way when we are ready to take on greater responsibility for being a guardian and custodian of the greater reality. Rather than thinking about this is linear terms it may be better to think of persona as dynamic home base that we ever return to for recuperation, birth, but from which we must venture beyond if we are to make contributions beyond the self.