Fun and why not. The aspect people are most likely to forget especially fun.
There are a lot of bird shots about on the web that have been taken with a mirror lens. These were designed for manual focus and in some ways much easier to handle than refractive optics. If anyone feels inclined to try it costs are relatively low. Some are hopeless exceptions being main camera manufactures branded ones and the Tamron adaptall BBAR. 500m F8 as smaller and faster one tend to have much to large a 2ndry mirror. There was also a Russian 1000mm one. That and the 500mm one enjoyed a good reputation.
I did come across a site that used a mirror lens for birds in flight with lots of examples but haven't kept a link. A gimbal mount may have been used.
John
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