The concept of holes is important, but it doesn't have much practical use. It typically only comes up when you're discussing the physics of how semiconductors work, or doing similar electron-level analysis of a component.

It's also usually brought up early on when teaching new students about circuit physics, but it's really not something that comes up in an EE's day to day.

Maybe it's more relevant if you're deep into analog or RF black magic, I wouldn't know.