Almost every deck I've ever made in Keynote cannot be replicated in PowerPoint. It doesn't have the same support for transitions that Keynote does. Good transitions (not flashy ones) are what make a good presentation great.
Consider perhaps the most famous presentation of them all - the iPhone release - I don't think the slide transitions got too much press, and I don't personally recall what they were.
These days my slide transitions are simple - slide 1 replaced instantly with slide 2. In other words no transition at all.
You may prefer a different transition, but to say it's the transitions that make the presentation great is reaching imo.
I get paid to make presentations, I've worked with other paid speakers, and I've seen 1000s of presentations. All the people who get paid to make presentations use transitions (and almost all of them use Keynote too), and there is a reason. Because it just looks "unprofessional" when you don't.
This book really upped my presentation game, and using transitions is in it with more explanation, if you're really interested:
Yes, you need good content and a good speaker as a baseline, but assuming you have that, the deck is what makes the difference.