It is not an advanced academic program. It is an enrichment program that allows student a very small opportunity to explore and experience their particular, self-identified areas of interest and/or talent--either something they wouldn't experience in the regular curriculum, or in a different/more in depth way, or a way that would be too expensive to do class-wide but can be managed with small group of students who are actually interested in the activity, etc.
The way I see it, this last part is a big deal with small budgets and huge numbers of students. Cost is a problem when you spread it across 110 students in the grade. If you find only 10 are interested a given topic, SEM allows the enrichment teacher to make a difference with those kids while spending far less. Targeted spending.
The program is going through some growing pains, but my kids enjoyed the few days they had of it. If nothing else, the experience of one adult dedicated to such a small group of like-interested students is worth the small amount of time they get to do it.
It is worthwhile for what it it is, but is not an advanced academic program. Advanced academic kids at our school are able to stretch in the classroom based on the progressive design of the curriculum, differentiation, pull outs, push ins, etc. At least at the elementary level, I prefer this to the crazy testing, appealing, and competition we read about in surrounding jurisdictions. Different jurisdiction, but this is a good description of what I am seeing in our DCPS:
https://www.winnetka36.org/sites/default/files/5/Differentiation_FAQs.pdf