Let us not forget Grant and Sherman were a team.
They did what they had too and won.
Not what was politically expedient.
(Although Sherman's Capture of Atlanta sure did help Lincoln win re-election, why? Because it showed that Union Armies were in this win it and were committed to winning now despite setbacks, just like Trump)
Despite what some folks will tell you georgia was not burned to the ground. Certain areas were but by no means all of the state. In some ways it was good because it allowed Atlanta to build anew while places like Savannah built in the past