Hey Manan Chawla!
Thanks for your feedback.
This video/article is mostly for beginners and helps them build a real-time application in no time.
The Firebase is pretty powerful for making this kind of applications and for prototyping things very quickly.
But I agree that's not the only solution out there and probably not the best one for all applications. I often use MongoDB as the database for most of my applications.
If you are interested in any other kind of technology, please let me know. I'd be happy to make a video or write an article about it.
Stay safe.
-Greg