The fact that your luggage arrives in your room a couple hours after you do isn't a problem if you know about it. And since the luggage gets delivered to the inside of your room whether you are in there or not, there is no reason to sit around and wait for it.
So if you know your luggage arrives a few hours after you do, there's no problem. I first used DME on May 8, 2005, its 4th day of operation. Our luggage arrived 3.5 hours after we did. I don't know EXACTLY when it arrived in our room because my wife and my 2 ore-schoolers and I were in the pool enjoying the start of our vacation. We had what we needed in our carry-ons, which is a smart way to travel no matter where you fly just in case the AIRLINE delays your luggage.
Think of it in the same way that you think of eating at a table-service restaurant. You don't walk in and expect to get fed immediately. You know there is a built in time lag in terms of waiting to be seated, waiting for your menus, waiting for the server to take your order, then waiting for the food to arrive at your table. All of that could take 30 minutes. But if you didn't know there was that time lag, and you didn't have food within 30 SECONDS of when you walked in, you'd call that a disadvantage or a downside to dining there. In that case, there was no downside at all. You know what to expect so you don't see the 30 minute wait for your food as a problem, you see it as just the way it's done, KWIM?