I think it depends. One could say the same about Redis, but it's wildly successful and people love it.
The difference is now they are advertised. Redis makes no claims to be anything other than what it is - a fast in-memory database that has some persistence capability but isn't meant to be a long-term data store. MongoDB, on the other hand, made (and continues to make) claims about being comparable in atomicity and durability to traditional SQL databases (but magically much faster!) that haven't withstood scrutiny.
Keep in mind, too, that most data ain't worth much. It's one thing to entrust data of low value in MongoDB; another to store mission-critical data in it. I would look askew at leadership who didn't ask hard questions about storing data worth millions or billions of dollars in MongoDB without frequent snapshots -- and even then, the value mustn't be contingent on the 100% accuracy of said data.