I've been writing for a few years now and I love it. Being ill I'm not able to do much of your conventional socialising but through letters I've met new people and become good friends with the people I write to and I hope to one day be able to meet those people.
Letter writing is my escape. You can lose yourself in creativity making origami butterflies and word searches and quotes etc to put in letters, learning hand lettering, doing little drawings or finding the perfect wording on a card or postcard to say to the person you're sending it to. It's a wonderful hobby.
Some of my pen pals have health problems too and though we can support each other with that it's nice to focus on the other parts of ourselves like what crafts we've been doing or what we've been watching on TV.
I'd recommend letter writing to anyone.
(Image description: pale blue background with a colourful collage of photographs of mail I've sent or received and my notice board which is filled with mail I've received)