Traditionally, the reason for the 'two-step" process of opening a Roll N Lock was that it let you secure your bed WITHOUT locking the tailgate. In other words, simply by locking the Roll N Lock, you couldn't open the tailgate either. This was particularly important back when most trucks did not have a locking tailgate However, you are correct that you had to open the Roll N Lock to at least the first stopping point in order to drop the tailgate.
Since almost all new trucks now come with a locking tailgate, many customers choose to install their Roll N Locks with the optional (included in some applications) "NT Kit". - with no tailgate extrusion. So the cover only locks to the side rails and not to the tailgate. The Roll N Lock applications for the new Titan XD ONLY come set up for installation with no tailgate extrusion (NT). Two reasons for this: The plastic tailgate cap is spaced away from the metal of the tailgate and makes using our typical tailgate extrusion pretty much impossible. Secondly, it APPEARS that all the XDs get electric locking tailgates as standard. BTW, can anyone confirm this? My Nissan dealer (who happens to be my brother) doesn't know. Anyway, with the locking tailgate, I pretty much keep my Roll N Lock locked all the time. So, when I hit the lock button on my remote (or on my door), the bed of the truck is secured. When the doors (and tailgate) are unlocked, I can open and close my tailgate while leaving the cover locked.
I also generally keep my Cargo Manager (another Roll N Lock product) pulled all the way back. This leaves about a 2-foot deep area to put groceries, boxes, whatever - and they stay there - not sliding up to the front of the bed under braking! In effect, a trunk. Then, I can still slide it out of the way or farther forward or remove it entirely if i need to use the bed of the truck as, well, a pickup bed!