Wow, just realized I didn't address your question.

Upsides besides battery life and turn by turn?

Not too many, altitude is more accurate and it records temperature during your ride (woo!). You can also set alerts for cadence, heart rate, distance, etc. to remind yourself to either keep your cadence up or your heart rate reasonable. But depending on the app you're using you may already be getting this.

Also, If you're using the Strava app, it ignores the speed input of the Blue SC and is using GPS speed instead which is also less accurate.

Besides that, if you're happy with what you got, you're not missing much