Because while far far denser and easier to parse by humans, it discards a considerable amount of data. I think it's perfectly sensible for the default toolchain to dump the most complete representation and allow users to use tools to get the representation they prefer.

Because this one involve checking duplicates and does a fair amount of logic. When the process is crashing, all bets are off and you may not be able to allocate memory for this processing. This is why they simply dump all there is to stderr and exit.