You will still get a paper copy of the bill if you select to receive the efolio. Since I run my own business, I do not need the bills for reimbursement.
I get the efolio for a few reasons. First, I want to make sure that my final bill is correct. I have had the rare occasion where I had to leave before checking out every detail on my bill. In addition, the times I do not receive an efolio or get one that has no correlation to my actual bill serve as an advance warning that I need to fix up a bill. I did not get a bill for a recent reward stay, and that stay did not post to my reward account (I did not get credit for the platinum welcome gift). In addition, I was charged for the award stay as well.
The efolios are also handy if you need to access copies of old stays, and you do not have the paper bill.