Extraordinary claims require extraordinary evidence.
Moses claimed to represent the God of Israel. He provided (according to the account) extraordinary evidence to back that claim that all could see.
This seems to be the case in most biblical accounts for leaders of God's people.
Wouldn't it be nice if it was that easy today?
It would be nice if proof could be provided without someone or something suffering or having to be killed.
Because of that very reason me thinks Bible is made mostly of stories to be taken with a grain of salt.
More figurative than literal.