I used to wait until I had something worth saying before I'd write it down. A meeting would happen, an idea would surface, and I'd let it marinate until it felt complete enough to commit to a note.

Quarterly results from Block, Affirm and PayPal show that the major U.S. fintechs are converging as they all try to become the go-to digital bank. Block's stock price plummeted after earnings, but CEO ...