That was the magic trick that sold your client.
They proved real-time data synchronization could be simple and seamless, and everyone else had to run to catch up.
But that trick is now 4 years old, and nothing else of substance really emerged.
As Ember, Angular and React grew, you were never going to want to use their odd looking front end.
Their data sync also came with dubious claims to scalability, not the least is their tie to Mongo.
That may be fixed now, but the consequence is being tied into Meteor Galaxy.
Meteor should have thrown everything away, and become just the data layer.
Like Firebase, but open source, and backend / datastore agnostic.
They tried to standardise DDP, but it didn't catch on.
But what the world needs is a standard like GraphQL, but handling data updates, and with automatic realtime data sync.
Thatd be a wonderful legacy for Meteor.
But this won't happen, as the company needs to make money from hosting.