DC Elite is using your host battery as a power source. While people can be subjected to subjective reasons. I will base my reasons on technicalities first and then subjectivities.
The D16 is a standalone DAC with it own battery source. Together with 16 elements of PWM where as ROHM and other flagship chips possibly have 5-6 as I read somewhere in this thread.
Technically, the D16 is a marvel of engineering feasts against DC Elite.
Now, subjectivities are always a thing, someone may be comfortable with just a small dongle and hook it up to anything easily. Then DC Elite will be a winner here. Sound performances and signature is where you would want to listen and compare to it yourself. If you need inputs from some people, it is obviously the more experiences that someone is, the more solidified his opinions are. For example, someone comparing D16 to DC Elite , putting against someone who comparing D16 to other DAC, the timbres reproduction of a real instruments on all devices like literally recording his own guitars, piano, and reproduced it...vs DC elite...etc..then I would take the one with more experiences as a superior inputs.
In this hobby where subjectivities are...an elusive matters. People can bend the facts, to hype and to shill something up. When it is wrong, it is just one single person opinion as a subjective conclusion. Together with the age of the internet where everyone can be an expert is very very hard to grasp as a concept and to be collectively correct on your researches.
Try your best to have an audition between these 2 devices and think about what you need, your budgets. Then you will always be happy that it was your call and not someone else