Let's rule out why you need nothing more than QBO to track expenses.
1. You can use QBO on any internet connected device, if you have a smart phone or tablet with a sim card or internet access you need no other device in the field
2. Enter expenses in QBO as they happen. "+", Expense. You can take a picture of a receipt and attach it, or not.
Yes, this generation wants to only take selfie with their receipt and have it automatically entered, categorized, sliced and diced and there are apps that let you just wave your phone at another and boom, your taxes are done. I dare this generation to add three three digit numbers and subtract a fourth, in their head, without a calculator.