Based on the generally good approximation of 10% ownership for series B investors, this wasn't a great return (if any) for Benchmark.
Pretty nice for the founders though, and likely nice for the users too - Zenly's product requires all/most of your friends to use it for it to be good, which is really hard to do, but Snapchat already has a lot of users, so it'll take Zenly's tech and turn it into something valuable.
Seems like a nice outcome overall!