Back when I was a music major in college, I used to compose minutes of silence into my music. The idea was that each period of silence got longer until people just assumed it was done. Before the performance, I announced that the audience should leave when they think the piece is over. If they got it correct, they got a coupon for pizza hut. Sadly only two people figured out that when the conductor got off stage, the music was over.
So I had silence with a purpose but it wasn't purely musically.
I'm not entirely sure if long extended period of silence within a piece of work adds any value. Maybe if someone thought that like 5 minutes of silence will somehow do something in the brain that would make the next section sound brilliant, but I'm not sure. It's art, people do things just because and that's good enough for me.
As for your second thingy. I don't know, it doesn't matter. I wouldn't say it was pointless or crap. It served it's purpose and if some composer can find influence from the concept that it sure did have a point! My own personal opinion is complete apathy though. Music is art, and sometimes nothing means more than something.