[kungtotte]

There's a large use case for simple personal bookkeeping that doesn't require double-entry accounting.

Most people have some fixed recurring bills (insurance, rent, subscriptions, etc.), some variable recurring bills (utilities, etc.), standing payments like savings, and monthly spends like groceries.

For them (myself included) something that lets you simply input recurring expenses and your income and show a running tally is pretty much all that's needed, add some simple transaction tracking and you're there. Basically all you really want is two things:

1) Given $2000 at payday, how much of that is available to spend if $X is going towards known expenses.

2) The day before payday I have $Y left in my account. Where did I spend the $2000-$X?

[chris_wot]

Which means you have to take out money from one account and transfer it into another. Which means that you need to understand that you must debit an expense as it decreases the owners equity credit balance, and then you must understand that it causes a credit on your bank account.

If you don't have this, then you won't be able to work out where you spent your $X amount of money.

[kungtotte]

I don't need to understand any of that for simple personal finance. A transaction with a negative amount with a to and from field is all that I need.

If I see 15 bucks each month going to "Spotify" I don't have to be a CPA to work out that I spend 15 bucks a month for Spotify...

[chris_wot]

Which is an expense, and it takes money out of your bank account and into the Spotify expense account.

You have just understood it, intuitively.