It sounds like a bargain for a free agent who hit over 30 home runs last year. Keith Law agrees. It gives the A's positional flexibility: if Daric Barton struggles as he did last year, Giambi could play first base, with Jack Cust DHing. If Barton hits, but Cust or Travis Buck struggles, Giambi could DH while Barton covers 1B, and either Cust or Buck roams the outfield.
It's almost a perfect fit...except...it's kinda like taking back the old girlfriend who dumped you for the richer, handsomer guy so many years ago. You loved her so much while you had her, then you hated hated hated her after she betrayed you. And now, taking her back? There may be some benefits, but I can't imagine that it wouldn't be healthier for the soul if everybody had just moved on, for good.
That is, if baseball teams have souls. Maybe they don't. In which case the analogy is flawed. And so is our fandom.