Me saying I used to present about the MBTI is very different from me saying I want to marry it and have its baby. ;-)
It's easy to get caught up in the apparent dualism of each of the 4 types. A deeper read of the thinking behind MBTI (and other personality inventories) shows that it is meant to express a continuum of tendencies.
Not every introvert perfectly fits the definition, just as not every extrovert does. If you tend to affiliate with more of the feelings and behaviors associated with introverts, then you more likely fall under that category.
There's no judgment involved. It's just a tool for understanding. If you know your tendencies and the natural tendencies of those around you, it can make you a more effective team member, life partner, etc.