I don't think a pin actually threatens the screened piece except technically - that is, to make the pin work. The real threat, if applied, is to the pinned piece which can be additionally attacked but pins are more often used just to immobilize a piece to keep it from taking part in some activity.
Quite the contrary, the real target of pin is the screened piece, that's why the blocker is immobilized and then you can put more pressure on it as you say, to cash on in.
That's not how I see it. To me there is seldom any expectation of winning the screened piece (the piece behind the pin). If there is any expectation of winning a piece, it's almost always the pinned piece. But again, neither piece may be a target - as I stated before, except in the technical sense.
Of course whatever one's perspective might be is fine.
What do you think about the phrase " ... two or possibly more threats..." @batgirl