Handy, no doubt. Where do blanket pardons end though? Say an anarchist gets elected (anything is possible these days). Can he pardon all people for all crimes committed between 1850AD and 10,000AD? Ridiculous example, I know, but blanket pardons are ridiculous in a just society. But, as they say, c’est la vie.
The president cannot pardon for future acts, only for past ones, and only for federal crimes, not for state crimes.
There are limits to the Presidential pardon power.