The lack of nonverbal information even exceeds telephone consultation. Consultants can basically only distinguish the lines of visitors' letters.
Communication cannot be instantaneous. On the Shrik-link website in the United States, psychologists can only reply to visitors within 24-72 hours as far as possible, so communication cannot be instantaneous.
In addition, another important problem is that the limitation of visitors' written expression ability hinders communication with consultants.
So generally speaking, online consultation is not suitable for making diagnostic conclusions for visitors.