'Crisis on Infinite Earths' sorely underutilized Black Lightning even though the character has the potential to be a true Paragon
From a writer's point of view, the best thing about crossovers is that you get to fit all your best characters into one story. The worst thing about crossovers is that you have to fit all your best characters into one story.
If even one hero doesn't get enough screentime, it reflects poorly on the story and that can be an issue because let's face it, you can't give equal focus to a dozen characters even if you have five hours to work with. Despite how epic The CW's 'Crisis on Infinite Earths' has been so far, this is the main problem that's got us a bit disappointed with the crossover event.
Seeing as 'Black Lightning' didn't have a full-fledged crossover episode, we didn't expect all the characters from the show to play a pivotal role in the event. And yes, it's only Jefferson Pierce / Black Lightning (Cress Williams) who gets to even show up during the crossover. To be fair, Jefferson did get to do something during the event, helping the Flashes (Grant Gustin and John Wesley Shipp) take out the Antimatter Cannon. However, seeing as the Anti-Monitor (LaMonica Garrett) still managed to destroy the multiverse, Jefferson's contributions ended up being all for nothing.
He didn't even get to be a Paragon, which is a position that Jefferson, with his strong moral code and sense of justice, was perfectly suited for. Ultimately, 'Crisis' would probably have reached the same point it's currently at even if Black Lightning hadn't joined the event and that's just sad.
Having Black Lightning appear in the crossover was certainly a nice treat for the hero's fans and it has definitely raised the profile of his show. But that said, Jefferson could have been given more to contribute to the event, seeing as he is technically a more experienced hero than any of the other Arrowverse leads.
'Crisis on Infinite Earths' Part 4 will air on The CW on January 14. 'Black Lightning' Season 3 will be back on The CW on January 20.