I can see how advantageous it is to import IIF files to QuickBooks Online (QBO), WBUMISH. Let's send this suggestion to our product engineers so they can consider adding this feature in future updates.
I recommend sending an enhancement request to our product engineers. They continuously seek to fulfill our customer's needs, and your input is vital in deciding which features will be incorporated in upcoming updates. You can temporarily utilize the QBO test account to send feedback since you haven't yet decided to migrate. Here's how:
Meanwhile, you may opt to find other alternatives to help you with your task. To choose the best application for your business, you can visit this page: QuickBooks App Store.
Also, we've compiled a list of frequently asked questions regarding the process of importing data into QBO. For further information, check out this article: Common questions about importing data to QuickBooks Online.
I'll be here if you have other feature concerns or need further assistance managing your business's financial data in QuickBooks. Drop your comments below, and I'll be sure to help you out.