Correct...it is just a printed confirmation of your trip. When you check-in, you actually don't even need it. Just give them your name & flight #, show your ID and they will print your BP.

IF you want to convert to 'paper', you would need to do it at a CTO or an airport counter.
From some of the info previously posted here, airlines (not sure about DL) are trying not to print paper tickets, and some have even levied a charge to switch from E-ticket to paper.

I've booked my last 6-7 trips via the web and never had a problem with the DL E-tickets.