As she doesn't need it to win, there are only 3 reasons for Clinton to go after GA:
1) Bragging rights. It's not entirely frivolous if she wants to present an unifying administration that carried the entire eastern coast of the south other than SC. Not to mention she'd want to start her administration off with as big an ass-kicking, mandate-granting victory as possible.
2) If Barksdale proves a serious competitor to Isakson and she might help him win. This poll indicates he's got a shot, but unlike Hillary he needs 50%+1 to avoid a runoff he'll quite likely lose.
3) Force Trump to spend $ there, weakening the amount he puts towards other states like PA and AZ.
The Fourth reason would be to expand voter registration, local campaign volunteers, and help build a foundation for future statewide (As well as Presidential elections) in a state that the Democratic Party has virtually neglected for many decades, effectively ceding that state to Republicans on all levels of government for quite some time.... Sure it would take investment in resources ($$$ and skilled staffers), but GA is much cheaper to invest resources in than TX, even though in theory there are demographic trends that favor the Dems in the long-term in Texas, so long as Republicans keep nominating candidates that don't believe that Mexican-Americans belong under the tent of the "Grand Old Party".
