I understand the need for low polygon count when making game assets. I understand also how realistic and object or seen can become if you use a higher polygon count. There is a place for both and I think it depends on what you are striving for. In a super-realistic scene (like a photograph), detail is extremely important on the objects of focus. However, that bush in the background or fallen tree may not even be in focus due to depth of field. So, why detail it with a higher than necessary polygon count.
In gaming, (at least until quantum computers are common) the need for low poly count is obvious. Bogging a computer down in unnecessary calculations would slow a game down to a crawl. (I have experienced that with a low quality graphics card on an open world combat simulation. By the time I get my character in position, Iām no longer a live player 
)
So, I think the decision to go low poly or high poly depends on what the scene is that you are creating in Blender.