What. The first thing any security paper defines is the assumed threat model. People design all kinds of schemes for different threat models.
The point with assuming conservative threat models for key primitives like hash functions is that the threat model can change rapidly even within the same application, and attackers only get stronger. So you err on the side of caution, and don't rely on luck to keep safe.
The point with assuming conservative threat models for key primitives like hash functions is that the threat model can change rapidly even within the same application, and attackers only get stronger. So you err on the side of caution, and don't rely on luck to keep safe.