It would be interesting to be able to receive a notification when the user is logged in and receive a notification audio. I use some sales gateway that has this feature.
Approved Sale - plays a specific notification audio
Declined Purchase - plays a specific audio for declined purchase
And other events too.
I say this because I am building a sales recovery platform and it is very motivating to hear personalized audio when a notification is received. (Example of sound effect: https://elements.envato.com/pt-br/money-bills-falling-onto-table-CAXNU3H)