Distinction: I am a millennial, and actually had to go look up just now what a "powerhouse" is. I am familiar with the term in its metaphorical sense, but was heretofore unacquainted with the literal definition. "Power plant" or "power station" would, yes, be more immediately understood by my generation. The phrase "Mitochondria is the powerhouse of the cell" would read to modern children like saying "The mitochondrion is the rock star of the cell."

These things do happen. I was in my 30s before I learned what the "firewall" of a car was...