I was recently in an HR meeting, where local vendors pitched us discounted services based on our employer affiliation. And everyone in the room got to witness both effective and terrible uses of metaphors.
A pre-order pick-up grocery service called MyGofer, pitched us this way. "You try and squeeze in your weekly grocery shopping after church on Sunday. But your kids are being crazy. Your husband is mad because he's missing the start of the Bears game. And the cashier doesn't seem like she values your time nearly as much as you do..."
One lady in the room started laughing and said, "Are you following me around!?!"
A perfect metaphor.
The next pitch was from an insurance provider. The idea was that you may be paying too much for home insurance. Because some providers make you pay for what it would cost to rebuild your house from scratch, post-catastrophe. But this provider will only charge you for the current market value of your house.
This is a real benefit. But, here's how he pitched it. "Let's say you own a $1,000,000 million mansion on a 20-acre estate. But, the house only takes up an acre of land..."
What? Now, to be fair, this is a metaphor. But, if no one in the room can relate to it, it's not a good one.
It's like when my allergist recently tried comparing my lung capacity to a carburetor. It may have been effective...if I understood how a carburetor worked.