Most people hop at DLR, since you get more flexibility and the parks are super close. Hoppers are a nice luxury to have, and if you feel you need them during your visit, you can always upgrade at the gates.
However, don't stress if you don't have them! I would like to share wih you some advantages of not hopping.
1. More time to relax: as someone already stated, staying in one park allows you to stop and smell the roses, and enjoy the hidden details in each park, instead of running around between the parks
2. Less walking and more time saved: Even though the parks are only about 100 metres away, it can be much further if you are heading from paradise pier all the way to toontown, say. And if there are long lines at the gates, then it could take you even longer, espeically if you collect FPs for both parks.
3. Different parks, different atmospheres: I know many hopper fans will disagree with me, but to some people, keeping the magic of DL and the adventure of DCA separate is a bonus. Some people take the transition from each park as too drastic, and prefer to think of them as two parks, instead of one big park. For those people, hoppers wouldn't be the right fit for them. This isn't the case for everyone, just different perspective on hopping.
Anyway, that is just my 2 cents. If you can, get the hopper, especially since DL oftentimes requires more time than DCA. I just wanted to shine some light on the advantages of not hopping.
