I don't want to manually have to scroll through all the release logs on every single upgrade, in case their might be a landmine in there this time. Nor does any rational person that values their time or their system stability.
It is a million times more sane to have a package manager throw a warning or an error when a breaking change is about to be applied, rather than just YOLO the breaking change and pray people read the release log.
It is one of the most stupid policies ever, and the main reason why I will steer everyone away from Arch forever. Once bitten, twice shy.