See this discussion about preprints which will never be published:

https://www.researchgate.net/post/When_a_preprint_becomes_the_final_paper

See also these related discussions:

https://www.researchgate.net/post/When_is_the_appropriate_moment_to_upload_a_preprint

https://www.researchgate.net/post/What_is_the_take_of_Reseachers_about_the_Preprints

Indeed it is premature to include preprints in the profile.

On the other hand, they have other benefits:

For budding, young researchers, it is admissible to include the preprints in their profile, so that the readers of the profile may have a chance to know where are the researcher's interests headed into.

For others it may advertise the current interests.

Preprint repositories assign doi before releasing it online. That means the manuscript could be cited.

Hence, it could be reasonable to include preprints to in researcher's profile.

More discussion is needed particularly regarding the inclusion in a researcher's profile before the paper becomes a full-fledged article, a point not well focused in the cases of many answers.

It depends on the stage of the preprint, for instance if it reached the accepted level but waiting schedule to be published like in the coming volume or issue of the journal putting it on the profile should be tolerated.