In the first step, you get everyone to invest into your platform. You provide some valuable services to people, and they sign an implicit contract as a result.

In the second step, you reap what you sow. You switch the platform entirely and change its core nature and functionality. It's hard to stop using Facebook when everyone else is using Facebook, and this fact means you can do things which would normally have people leave your platform in droves.

This ruling limits the extent to which you can run such a bait and switch campaign. It's somewhat remarkable, because it extends some basic consumer rights to tech companies, even if there's no direct product nor a subscription in place. Personally, I think it's long overdue.