Because it magnifies the lack of clarity problems in the current poor examination process which both makes litigation between market participants in comparable positions more likely and makes market players with less resources more compelled to knuckle under to those with more because they can't afford the risk of litigation. The greater clarity is provided in advance, the less uncertainty/risk is involved in litigation, which both makes litigation less common and reduces coercion of market participants by those more able to afford risky litigation.

> For whom?

Pretty much everyone, though less for the richest players in the market and the patent lawyers.