Cadillac president Johan de Nysschen presented the latest addition to the brand's high-performance V-Series, the 2016 CTS-V sedan, to the media last week in Detroit. Source: General Motors.

Why does General Motors' (NYSE:GM) Cadillac need a high-performance sub-brand?

It's an interesting question. For years, Cadillacs were thought of as "a couch on wheels," as the brand's marketing chief, Uwe Ellinghaus, put it in a conversation with us in Detroit last week.

But times have changed. German luxury giants BMW, Mercedes-Benz, and Audi have all shown that high-performance luxury cars can sell -- and sell quite well.

But the business cases for cars like BMW's M5 -- or Cadillac's CTS-V -- go beyond profitable sales. These are brand-builders, models that have a "halo effect" on the other cars in the automaker's lineup.

Cars like the CTS-V also get car enthusiasts excited, and car enthusiasts are often asked for their opinions on cars by friends and acquaintances. If a well-heeled enthusiast is singing the praises of the latest Cadillac, his BMW-driving friends might take notice -- and check out a Cadillac themselves.

We knew that much, but it turns out there's even more to the business thinking behind high-performance luxury cars. At last week's North American International Auto Show in Detroit, we spent a few minutes with Cadillac president Johan de Nysschen, who came to the show to introduce the all-new 2016 edition of Cadillac's hot CTS-V sedan. We asked him to explain why the high-performance V-Series models are important to his efforts to make Cadillac a global luxury powerhouse. Check out the video below, shot right on Cadillac's show stand, to see just what he told us.

John Rosevear owns shares of General Motors. Rex Moore has no position in any stocks mentioned. The Motley Fool recommends General Motors. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.