There are countless ways to tie your belt from the superlock (never comes undone) to the standard to the old school Gracie way (picture). Having seen the way Master Relson Gracie ties his belt, made me notice that many members of the Gracie family (Helio branch) and of their main acadmies like Gracie Humaita, Rickson Gracie academy, Relson Gracie, Rorion Gracie etc.. tie their belt in this way. The main difference from the standard way is that instead of looping over both sides of the belt, the knot is just on one side.
Are there any advantages to tying your belt this way? Not really. The belt knot isn’t really tighter. It just looks cool and makes you look different than your other training partners and differs you from other similar sports like judo for ex. Here are some famous Jiu-Jitsu players that sometimes tie their belt like this. They don’t always tie their belt like this though. At the end of the day there is no golden rule in Jiu-Jitsu on how to tie your belt. Just feel free to tie it how you want to.