I agree with post 158 just above from
@Feiertag (though I respect the opinion of those who do not like contests). I have a large collection of the annual awards issues of
Natures Best Photography and a large collection of the annual book of 100 winners from
Wildlife Photographer of the Year (from Portfolio 13 through the latest Portfolio 32). I have also seen two editions of
Wildlife Photographer of the Year exhibition in person at Natural History Museum in London. I occasionally re-read them and seeing these images is a joy, which would not be possible without the competitions. A few of these are pros who might publish the photos in their own books, but not the majority.
Wildlife Photographer of the Year staff also state (and I believe them) that some working nature photographers launched their career by placing in the competition. To these people obviously contests hold a lot of value!