Honest question, what's the "Explain like I'm a Freshman" for what they can work out/leak from all the spectre stuff?

I see alot about private keys etc etc, but is just a blind attack? Or do you need more info on the target? How quickly can you attack to get info?

In essence, is this something Joe Public needs to worry about their $5 vps, or something nefarious using against $CORP's public cloud infrastructure?