Well it's heat displacement is going to be less than regular aluminum unless you use some sort of fan. I would say normal copper would still work better.
That would be even worse than having just air as a "heatsink" because the gas inside that foam is trapped and can't convect away. Metal foam is made to provide strength for low weight, not for heat transfer capabilities. In fact, the foam essentially act as insulation, like styrofoam, only with aluminum rather than polystyrene.