Gal D. Great question! Here's the difference:
Themes are style sheets. They define colors, fonts, and visual design. When you generate a presentation from a theme, Gamma creates the content and structure for you, applying that theme's style on top.
Templates have pre-built structure and narrative flow. They're designed to be reused with your own content plugged in.
That's why generating from a theme feels more robust. Gamma is building everything from scratch using AI, rather than just filling in a pre-made layout.