Side bends when holding the weight overhead--is this an effective obliques exercise?

I can't recall where I found this exercise, but you basically hold a weight above your head with both hands (or it can be two separate smaller weights in each hand), tighten up your core, and bend to the side while keeping your arms straight overhead and pushing yourself back up straight with your obliques. It feels really effective when I do it throughout my entire core, and seems like you can get a much more intense workout with a smaller weight.

However, I recall reading that normal side bends (where the weight is down at your sides) are not effective if you have a weight in both hands because they balance out. Would that apply here as well?