Application is the fastest way to store information about your expenses.
It is optimized to be used when standing in line or just after paying in shop.
You enter expense data right after starting app so you can do it right after having actual expense. This will assure you don't forget to add it.
It is ideal supplement of your account statement during your home budget control. When you withdraw money at the ATM you can write a note why you need them (cinema, to buy shoes, etc). You do similar thing when you pay with cash. That way you can later check if you spent those money to things you plnned. You will easily match your expenses to data from your account statement.
The same thing goes for buing online.
If you sometimes wonder where did your paycheck go and your account statement doesn't give you enough data, this app was made for you.