While it's not known yet if this will be a weekly occurrence, it's a nice way to keep those streaming numbers up. Offering live viewers an opportunity to get additional content, could keep those hardcore fans watching two nights in a row. SUPERMAN AND LOIS already broke records for the CW when it comes to ratings for Live+3 (which factors in streaming numbers) with over 2.7 million viewers.
So what important scene was left out of the episode that aired on TV? It certainly wasn't a brief moment between Clark and Lana. Instead it was an important exchange between Sam Lane and Superman.
In just two episodes, we've come to realize that General Lane accepts Superman as an ally (see also: weapon). When Captain Luther fails, yet again, in acquiring kryptonite from a military complex, Superman demands to know what he's looking for. That's when General Lane comes clean about his dirty secret.
He's been stockpiling kryptonite.