My understanding is that the era of frivolous James Bond films began with Diamonds are Forever. Diamonds are Forever starred Sean Connery, which unfortunately didn’t work out very well. Therefore, Live and Let Die marks the beginning of the genuinely enjoyable silly Bond movies. I'm a big fan of Connery—a devoted member of Team Connery, you could say—but even so, Live and Let Die remains an excellent 007 film, despite the significant shift in tone and character. The films transitioned from portraying a cold-blooded killer to embracing more comedy and special effects, which suited Roger Moore better. This new direction for 007 made the unfamiliar setting effective. While James Bond had previously appeared in America, Harlem in 1973 and New Orleans were locations where a privileged British man would be conspicuously out of place as a spy. He’d stand out noticeably, and he does... ...and that's likely why they selected this location to introduce Moore’s version of Bond. Because Moore was going to be different; he represented something new within the franchise, and the setting emphasized that change. However, it didn’t matter—it was a silly Bond film, but it was also an enjoyable one. It offered entertainment in a way that Connery's films hadn't, but it was still entertaining nonetheless.

Source on TMDB