Writing it down makes it real.
For me, using a financial app to track where my money is going doesn't quite provide the same type of accountability. When I put the costs into my notes, I started to realize that the money was actually gone. Finito. Vanished into thin air. Looking at the amount you spent at the end of each month doesn't make you feel, well, anything. Looking at the amount you spent in that moment, though? It makes you question whether the purchase was worth it. That $4.95 I spent on a skinny vanilla latte from Starbucks that was burnt? Total bummer. That $36.78 I spent catching up with old friends at Earl's? Total win.