Because I have different interests and talents.
Thus, I see myself more as a generalist than a specialist.
Meaning: I have know-how and abilities in various fields, which gives me flexibility and the possibility to establish links more easily.
Yet, my know-how and abilities might not be as advanced and efficient as they would be if I would have specialized in one or two fields.
That means for my work-process that when I reach a point where efficiency and specific know-how is needed, I delegate the work to others/cooperate with specialists.

However, this way of describing things is only valuable if perceived from the point of view that there is a person with certain features, whereas I would suggest to regard all this as a dynamic process occuring.