It's a "mode"?  My understanding of this question is: "Is it really necessary? Is it here to stay?"

I am sure the answers are: "Yes, and yes". Why?

There is no doubt that many Poser users want and expect to see good images coming straight out of Poser. Many amateur/hobby/casual users are disappointed and discouraged by their inability to get anything approaching realistic lighting and shading in their renders.

They can take a normal snapshot with their digital camera, upload it to their computer (as a JPG image) and display it on their screen, and it looks fine. But they set up a simple scene in Poser and display the render on their computer screen, and it looks horrible. Why? Well, at least partly because their digital camera automatically corrects the image so that it will look right on a computer screen; but Poser does not.

They are confused by the explanation that it is their own fault because they are not Gamma Correcting their renders. They don't understand why it's necessary, they don't have the image editing software required to post-correct images, or they just don't know how to do it.

Many people, many different reasons, but one consequence: many images with no GC being displayed on computer screens that require images with GC.

So the latest release of Poser (Poser Pro) has a built-in Gamma Correction capability. This must be a good thing for many users, and I believe it should (and will) be a standard feature in future mainstream Poser releases, not only in the "Pro" version.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)