Below, we discuss how table-updating is prone to bulldozing your beautiful design, whereas chart updating is not. It may make the updating process redundant in terms of efficiency gain.
Ideally, you want it to go directly into PowerPoint (one-step).
If you expect everything to be updated, then see the first consideration above. External packages can only "talk to" PowerPoint and "ask it" to do certain things. Microsoft isn’t going to redesign PowerPoint to suit an analysis program (including a large player like SPSS).