I have a fairly elaborate spreadsheet in (Apple) Pages that tracks incomings and outgoings, savings & investments etc, but then I’m working with a number of different accounts and it helps to be able to see everything in one place. It also helps me figure out where I’m going to be in the future. If I pay X into this savings account, at Y interest rate it’ll be Z a few months or years down the line.
It’s especially useful for tracking investments, working out the value of the shares I have based on their current price. However, it also shows how much I’m spending on subscriptions and leads me to question whether I’m getting value from them --most of them have been culled now!