Why use the Present Perfect Continuous
Both the Present Perfect Continuous and the Present Perfect Simple express continuity. However, continuity is only one of three possible meanings of a Present Perfect Simple verb, while it is the only meaning of a Present Perfect Continuous verb.
- I have worked as a pilot for 10 years.
- Immediate Past: I have worked as a pilot for 10 years until now.
- Experience: I have experienced working as a pilot for 10 years sometime before.
- Continuity: I have continued working as a pilot for 10 years until now.
→ Since there are at least 3 different ways to interpret this expression, it is not clear whether the action is continuing now, unless the context tells you.
Present Perfect Continuous:
- I have been working as a pilot for 10 years.
→ Since there is only 1 meaning (I have continued working as a pilot for 10 years until now), it is clear that the action is continuing now.