Needless to say, I am also very skeptical of identifying gifted students at a young age. IMO society over-values so called natural talent, and trying to find that talent in an 8 year old is silly, with rare exception.
Now, many of my higher performing peers from 3rd grade are lost. Hopping from career to career, city to city without a sense of direction. A few of the high performers have gone on to do impressive things, but nothing shocking, nothing that is any more impressive than what my stoner friends and I were able to accomplish after a few extra years to mature.
It took me more time to find that what I really enjoyed was engineering and math. Of course, this is a first person account, so take it or leave it. Worth noting that there is a whole lot of very bad education research, so anyone whipping out journal articles to prove a point should be cautious.
The problem with treating "gifted" students differently is similar to gender bias in STEM, and racial bias in education overall. Some people are told they can, and other are implicitly told they can't. These messages get internalized by students, especially if you are unlike myself and don't have a mother who will stick up for you, and take you out of that remedial math course.