Trends in photography
Photography and its many techniques have always been subject to trends. In the 1970s, when this particular photograph was made, almost every photographer wanted to own a fisheye lens. It was a bit silly, because the lens would use less than half of the already small 135 mm film negatives.
Still, there really is no harm in playing around with lenses or cameras, because it may bring new ideas or new angles on objectively looking at your imagery.
Writers are known to suffer from writer’s block, and I strongly believe photographers can experience similar periods of feeling unable to produce work for weeks or months. Fiddling around with silly toys like this old Canon fisheye lens might actually open some doors that seemed locked.
In general, experimentation is always a good idea, but you might want to ignore fisheye lenses. They rarely help you create interesting material.