Cultivating brand advocates within a community sounds like a good idea.
You get a bunch of people together in a community, increase their loyalty to the brand, and watch them advocate for the brand in the future.
Can you spot the logic jump there?
Advocate for the brand where exactly? Advocate for the brand in the community? An audience that probably already purchases from you?
Or advocate for the brand outside of the community? You mean you want to send your top members elsewhere to shill for you?
Or perhaps advocate in their day to day lives? How many people will this reach? 10? 50? Not many. Certainly not as many as you could reach if you spent that time elsewhere.
This isn't to criticise brand advocacy. It's to highlight that communities generally aren't the best approach for cultivating advocates.