A person walks into a car showroom and says “I want to buy a car.” The salesperson says, “Do you mean that red Mini with the black stripes, two doors, grey interior and run flat tyres?”.
It’s the same with plants.
A garden owner once said to me, “…the ones with the spiky brownish leaves near the front gate.” Then there was the customer in the garden centre who said (and this is true), “I am looking for a plant to buy - something green.”
By way of contrast there was a time, I was told, that at the Wisley plant centre when someone mentioned a plant by its common name they would respond with a haughty air: “Oh you mean an Ophiopogon planiscapus nigrescens!” - or whatever the plant was.
The point is that there are so many plant choices that by using the latin botanic name you can be ultra specific. Otherwise we’re all struggling to focus on the right thing.
Do you need to have an encyclopedic knowledge of botanic names? Absolutely not. Just an awareness, or an online reference will do.
My neighbour talked to me about her ‘Red Robin’. I knew exactly what she meant and that was fine (and it wasn’t the cute, friendly bird that appears in every garden). But if after a conversation like that I am ordering a plant then so long as I am clear what the client or customer meant and wants then I can be 100% specific with the supplier. Then it’s smiles all round, not tears, when it turns up.