Erm, JJ's been profiling since season 1, it just wasn't in her official job description. That ep where Hotch asks her why doesn't become a profile? It's in season 2. Being the media/police/family liaison requires some profiling skills, otherwise they'd have to deal with uncooperative cops all the time and rate families.

Plus you've no evidence that this will give her more screentime above any of the "real" profilers. It's a way to develop her character.