After phishing attacks, Chrome extensions push adware to millions

Does anybody remember this? Why do we assume the adware was the end result and not just a vector for something worse?

https://arstechnica.com/information-technology/2016/12/milli...

After getting hit by this yesterday and finding it not very easy to find which extension was affected I went through a big extension purge. Most of the extensions I had installed I never really ever used.