Hi Dragonflame,
Nice comparison to your bank account. Avast on your pc needs to synchronize with the update servers. If you happen to have an offline overview of your bankaccount, would you want the spreadsheet or dedicated program to warn you the overview is outdated? That would imply some form of synchronization with your bank, without you being aware of this action.
Using default settings, avast already does let you know when a program update is available, see the attached file. I must admit, I don't remember if this is in the form of a popup or something else.
Best regards,