There are some important differences, of course. Facebook owns multiple properties that mount competition to Snap Inc: Instagram, Messenger, Whatsapp, the original Facebook; Snapchat subsumes all these usecases in a single app that you'd be hard-pressed not to find on a teen's phone today. And it does so by making it optional to curate a permanent, indexable, discoverable, idealized public identity.
To many, that's strictly better than anything Facebook has put out -- a company that nonetheless commanded a high valuation, performed an IPO (albeit rocky), and now posts a strong profit.