The Hide Account Balances setting has three options in addition to the default state which is to just show everything — all of your balances.
The first Toolkit option is to Hide All. In the screenshot below you can see that all balances are hidden — both individual account balances and the Account Type total balances.

Two additional options allow you to choose which balances to hide. Hide Type Totals (below) hides the sums of your Budget and Tracking accounts but displays individual account totals.

Hide Account Balances (below) hides individual Account balances but displays the Type (Budget and Tracking) totals.

I can see a few use cases for this setting, especially Hide All and Hide Type Balances.
If you’re coming from a long history of making spending decisions based on your account balances (as opposed to the YNAB method of making decisions based on Category balances), hiding your account balances from yourself might help you modify your behavior. And I’m a big fan of using whatever tricks are available to help effect healthy, positive behavior change.
Similarly, if smaller individual account balances don’t impact you psychologically but if the larger total number freaks out your brain a little, hiding the total of your Budget accounts and your Tracking accounts might work to your advantage.
There’s also a case to be made for being able to hide these balance for privacy reasons — if you work on your budget at work on your lunch hour or if your roommate has the unpleasant habit of looking over your shoulder.
Comment Policy: You're entitled to your opinion and I appreciate you taking the time to share. However, I reserve the right to withhold any comment that doesn't add to the conversation or isn't in keeping with the tone or purpose of this site.