I loved the movie. But, I love style and tension. The whole movie just has many, many intense scenes. Very typical PTA, and maybe his best movie.
In my opinion, to understand the award love, you have to consider a Straussian (read, slightly hidden) interpretation of the storyline. I'm not going to worry about spoiler alerts for a decade old movie, but here is my take:
The piece at a 30,000 foot view is a criticism of the protestant work ethic and American exceptionalism. The tension is between the man (Plainview) who worked hard for what he wanted and ultimately succeeded, spectacularly, and the religious institutions that existed in Plainview's community. Without all of the hard work by the men that worked for Plainview, his success would not have been achieved. The foundation of that work ethic is, in part, the worker's religion helped fuel that. The priest held some power over Plainview because the church held some sway over the workers. Add in a little side commentary that religious institutions do not always have pure motives, and you have the stage set for a back and forth between the religious and economic foundations of hard work pays off and why America succeeded so spectacularly.
The protestant work ethic is a delicate balance that people will work hard because that is a virtue, and there is an expectation that hard work will pay off. It doesn't work anymore when the cultural institutions start to take advantage of people who work hard for virtue's sake, including both the economic and religious institutions.
In the end, greed and ambition won the game. American greed drank the Christian milkshake, and faith in our institutions are not where they were in the 1940's and 1950's.
TL;DR - Award judges saw this as an anti-capitalist and anti-Christian movie. Paired with all of the rest of the spectacular things in the movie, it got a lot of award love.