If I miss a few Ubers and a few airport meals that I should have filed expense reports for, that's real savings to me as well. That might be a harder use case (separating the fly shit from the pepper in terms of personal vs business).
There's a lot that can be captured and recovered after the fact if a system can surface "hey, this is 75% likely to be a business expense; have a look!"
I have a business CC available for most of my expenses. It's enough of a hassle if I accidentally put a personal expense on the business card relative to the converse that many business expenses end up on my personal card. (This is typically where I use stored payment methods on the same vendor for personal and business charges [Uber, AirBnB, Amazon, Paypal, NewEgg, Monoprice, Delta].)
If Truffle operates like KeeperTax (https://keepertax.com/), you can set the ground truth to the CC statements; the user only needs to augment this CC statements with occasional meta-data (what was the business reason for the meal?), etc. -- fundamentally the user can work completely in the tax app.
If you need to submit expenses, working with your statements is a much worse model, because of the need for the user to associate receipts. Receipts are the model the employee should work with; statements are for validation.
Also for the meals it doesn't really help much unless you already keep every receipt.
I generally have iPhone snaps of any receipt that is a business expense. I just don't always get around to doing the paperwork afterwards...
But in the case of meals, you would definitely need some documentation like notes on the purpose of the meal.