> json.tool produces more readable representation. Your option is opposite to this purpose.

That is correct, though I'm not sure what point you're trying to make.  The purpose of minifying isn't to make the input more readable; it's to condense it in the interest of sending fewer bytes over a network.  Unless I'm missing something, json.tool doesn't have the single express purpose of prettifying, since it also serves to be a validator as stated in its help message.  This is just aadding another commonly-sought option.