What confidence means here
Confidence reflects how clearly the app could see your motion — lighting, angle, frame rate, and whether your whole body stayed in view. High confidence means the read is well-supported; low confidence means treat it as a hint.
This is deliberate. A tool that always sounds certain is easy to trust and easy to be misled by. SwingVantage would rather tell you when to take a read with a grain of salt.
When confidence is low
Do not throw the read away — improve the input. A better-lit, better-framed video usually lifts confidence a lot. The next course is entirely about that.