The verdict
For a small team that makes a few decks a quarter, I'd stay with PowerPoint alone. The web version is free with a Microsoft account, and the desktop apps come with Microsoft 365. Add Plus AI when building first drafts has become a regular drain on the week, for example in a sales or consulting team that turns reports and call notes into decks.
If you want to build decks from scratch without any slide tool, neither is the right fit, and a standalone AI builder is worth a look. Whichever you choose, keep one master deck and a short list of approved slides, so brand and numbers do not drift.