There is a huge difference in the feeling of the film based upon the Frames Per Second it was shot in.
There are a number of films that were shot using a digital camera, but at a higher 30FPS that were reviewed to have a "poor quality or feel" because the faster shutter rate gave it a television feeling.
Many professional digital camera now shoot at the slower 24FPS to capture that film feeling.
Many faster 30FPS digital cameras often produced a cleaner, sharper, wider range of color image that was perceived to be to different from traditional film stock. That the color space and feel of film could not be reproduced digitally. Much of this is true.
Today, many digital cameras now use all the same lens, hardware and mounts that older traditional film cameras used. The sensors are much more refined and adjusted to give a more natural color space. Post-processing has also greatly improved to reproduce many film stocks as a digital filter.
If you were speaking to someone who was not technical, but experienced in the film industry. He may have experienced producing films at 30FPS which were much sharper and cleaner then traditional 24FPS film stock. As a result. I can totally understand his perspective that 30FPS has a higher quality image.
The techniques to produce 30FPS and 24FPS films at one time was very different. Today, it's better to clarify that the difference is not frame rate, but film versus digital.
Additionally, frames per second can have a direct impact on the type of motion blur produced in an image. The higher the frame rate the less motion blur there is. Resulting in a cleaner sharper image for objects in motion.