This may continue to work, as long as performance is not your primary consideration (you have little data and few queries), you don't have to evolve the schema much, and no programming errors or ad-hoc updates introduce data that fail to follow the schema at the DB level.

So, it might be adequate for a small and carefully maintained project, likely like many alternatives.

Or do you use a high-load, distributed, replicated / sharded Mongo configuration? Then I'd gladly listen to more details.