I wrote a paper on this a few years ago, with great colleagues
I snooped everything 'encrypted' from the first 'Smart' device I bought for research, a 55" Sammy 3D telly.
It neeed a bit of AI/ML but basically could profile all the Smart TV's owner's Wi-Fi traffic, political affiliation, nationality etc by cross referencing the encrypted but analysed packets against similarly chunked Alexa sites, till we found a match.