Hello,
Online banking rules go beyond the automatic memorizing and categorizing that QuickBooks Online does. For frequently downloaded items, rules can save you a lot of time by scanning bank items for certain details you assign for specific payees and categories.
This is a really great question. I'd be happy to shed some light on this for you.
When a bank rule is set up in QuickBooks Online, the rule will apply across all user logins. That means that regardless of who's logged in, the rules will remain the same in your Bank Feed. That being said, if you're an accountant and you set up a bank rule for one of your clients, this rule will only apply to that one individual QBO account. Setting up bank rules can't cross over multiple accounts, but it will certainly work regardless of the user logged in.
For more information about Bank Rules in QuickBooks Online, take a look at this article: How to set and use banking rules for downloaded transactions.
I hope this helps clear things up for you.
Cheers!