Think of a frame rate as a still image captured by your camera. Videos are just a series of still images stitched together which then appear to show motion to the human eye. Frame rate is measured in “fps”, or “frames per second”. 30fps indicates that there are 30 still images captured per second, and so on.
In application, this means that the more stills that are captured per second, the more opportunity you have to slow something down in edit whilst playback maintains its smooth appearance. Choosing a slower frame rate provides a jumpier cut sequence on playback when stretched in the same way. Neither is right or wrong, they just give a different creative output.