My take away from the Talk was that:
So as our Carbon footprint can impact the world so can our digital footprint impact our personal life.
Every thing we do on the internet is stored somewhere and have a price.
For our young people this is very important because they may yet want a certain job or desire to enter a certain college but their digital history can impact them entering their future dreams.
I too agree with your first point that our digital footprint can affect us personally, and indeed it is true that cyberspace (the cloud) stores everything, even when think we deleted a text, a comment, or an email.
Yes, a digital footprint is important or should be important for young people who are just starting to pursue their dreams. However, it seems some of them have not gotten to the point where they actively protect or care about their digital identities and are more into popularity - competing for likes - with their inappropriate posts.