if chrome fully adapts this, this might well be a full blown commerical by chrome for people to switch to firefox. i have been only using chrome only to run our projects locally and test it out.

It should be noted that “being certain of the environment the pages run” requires controlling the client software being executed which requires preventing the user from modifying said executable which requires the browser to either be closed source or, more effectively, controlling the user's hardware via blackbox verification chips (e.g. TPM DRM). It's not just advertisers that would benefit but any website that wants to DRM content.

I'd guess it's first gonna be used for streaming TV shows

I thought they were already being protected by DRM.