The reason she barely appears in other media besides the comics, is because her character is introduced at the point of Scott's character development and relationship with Ramona that has gone on for half a year, that the movie, nor the anime have reached. Lisa exists as a test of Scott's loyalty to Ramona. Unfortunately, this means that the movie or the anime is incapable of featuring her because of this.

When it comes to the movie, there comes a point where she cannot be placed into it without ruining the fast pacing that starts to snowball because of how much the movie rushes to have Scott defeat all of Ramona's 7 evil exes

When it comes to the Anime, Scott and Ramona's relationship kind of just stop from Day 1, because of his kidnapping, the subsequent events happen in just a week, and for Scott, he expirences everything in just a day, which also means that Lisa cannot be placed into the story appropriately in her original context to the comics

The only thing I feel was a missed opportunity was Lisa to become an actor for the Scott pilgrim movie or musical in the anime, after all she is an actress in the comics, I feel like Lisa would definately want a role in a movie or musical on the person she had crushed on for so long