I think many well-intentioned, but not very astute, Ts get caught between competing intentions: to be available, nurturing, rescuing perhaps vs really understanding analytically the psychological impact of how such contact functions. Also younger Ts have grown up with the technology of living life via text/e-mail, and perhaps underestimate the burden that such contact can become.

E-mail just wasn't so in use when I was in therapy. I don't know if my T even had an account. He encouraged me to call any time, and he had an answering service to take the calls. During acute crisis times, he encouraged me to call him directly. He always returned my infrequent calls, often within the hour. When I called the service I always made it clear whether I needed to hear from him ASAP, or at his convenience about a scheduling change.

I wrote a lot in the first 2 years and brought the writing to session for him to read.

But... I wonder.... is part of it about containment? Like, by not interacting outside of the session, it makes it easier (?) to contain all the emotional stuff in the session itself, so it doesn't spill into the rest of your life?

This is a pretty mainstream analytic viewpoint.