Letters make you finish your thoughts. Texts let you drop them halfway.

A letter has to arrive finished. There is no next message to carry the rest, so you end up completing the thought, finding the end of the sentence, deciding what you actually meant, all of which a quick reply lets you skip forever. The form does that work on you, not the paper.

Write one long thing this week, by hand or not, and send the whole thought in one piece. Make yourself get to the end instead of stopping where it turns difficult. You will learn something about what you think, which is the part a thread cannot give you.