I would say that the only thing that seperates Vampires from other Kin types is feeding.
While all Kin essences
can feed, and most of the Kin I have ever met have said they do feed in some way, the difference between them and Vampires is that they don't really have to.
Their essences produce enough energy to sustain them and so finding supplements is not an urgent requirement for most of them.
But Vampires have to feed because their essences do not produce enough energy to sustain them. It becomes a compulsive need that cannot be ignored.
If a Vampire essence does not feed it begins to take energy from the physical body, which results in the body becoming tired, lethargic, forgetful, and, as time goes by and the liver produces fewer red blood cells possibly even developing anaemia as a result of sustained draining by the Vampiric essence it carries.
The only other Kintype to react in such a way to a lack of energy is the Were, who under certain circumstances will feel the sudden and urgent need to feed. But this feeling only occurs occasionally and infrequently for most Weres, whereas it is a constant daily feeling for Vampires.
Some Weres say they get feelings such as this around the full moon, when they seem to become restless and ennervated, this would make sense as when they feel like this they would burn more energy and so the essence would be unable to supply enough to meet the demand. You may have some experience of this yourself, though of course not necessarily around the full moon.

I think this answers your question Wild, but if all it did was give you more then ask again and I'll see what I can do to help you understand.