That's the entire idea behind Firebase. It makes prototyping much faster. I don't know how well it scales, but it works for most smaller projects.
It all depends on what you need to actually do. The only real weakness of Firebase is the Google lock in.
Let's say you have an object called box.
It has 3 properties, the id, it's name and it's weight.
4 months later you add a 4th property. Cost, odd records that don't have a cost just return null for that field.
That's the entire idea behind Firebase. It makes prototyping much faster. I don't know how well it scales, but it works for most smaller projects.