Much of (if not the vast majority of the 'worthwhile') traffic you're intercepting is still encrypted packets though.

Not to minimize the recon value of the plaintext stuff. But not really fair to say you're 'bypassing' any encryption but for the WPA-specific kind.

People who use or rely on client isolation want to prevent inter-client attacks, for whatever reason. We show that this can often be broken. This can be problematic when you have older hardware in your network that is rarely updated, and many then rely on client isolation to mitigate attacks. If everything is encrypted and properly patched, then our attack indeed has less impact, but then there also wouldn't have been a good reason to use client isolation in the first place ;)