1. Nintendo has highlighted Super Smash Bros. Ultimate as one of the Nintendo Switch games that feature Luigi, in an effort to promote the upcoming release of Luigi's Mansion 3 HD. The article notes that Luigi has been a playable character in the Super Smash Bros. series since its inception, and his inclusion in the popular fighting game franchise has helped to increase his visibility and popularity among Nintendo fans.

2. The article also mentions that Luigi has appeared in various other Nintendo Switch games, including the Luigi's Mansion series, the Mario franchise, and the Mario Kart series. These appearances have further solidified Luigi's status as a beloved and iconic Nintendo character, and have helped to build anticipation for the release of Luigi's Mansion 3 HD.

3. Finally, the article suggests that Nintendo's decision to highlight Luigi's presence in multiple Nintendo Switch games is a strategic move to generate excitement and interest in the upcoming release of Luigi's Mansion 3 HD. By drawing attention to Luigi's widespread presence across the Nintendo Switch library, the company is likely hoping to capitalize on the character's popularity and drive sales of the new game.