Yes. You see the numbers Suze sell in France and you’re wondering who drinks the stuff because you never see it anywhere. It’s mostly consumed in mountain resorts (as are most gentians). And cocktail bars, now, of course.
As for the marketing advantage… It’s name recognition. Suze is the oldest of them all, and probably the first branded gentiane. Salers and Avèze are brands from the 1920s, with a very regional profiles. When they where launched, Suze had been around for 30 years, doing some great work. Gentian liqueur, lemon syrup and seltzer is one of the great forgotten French apéritifs, but the words ‘Gentiane Citron’ (as the stuff is generically called) only appear together a full decade after the words ‘Suze Citron’.
In more recent times, the fact that Suze belongs to Pernod Ricard has only helped (by the way: Suze was the only PR product in a White Negroni when it was invented - now all three original brands belong to the group.)