Is my conclusion right or did i miss the point ?
I believe you missed the point…
For one, both can be used for real-time application. All it really is execute AJAX call to backend and replace HTML element on callback.
MongoDB vs MySQL. I believe PHP can use both… So, it depends on the nature of the data. I haven’t use MongoDB with this crazy NoSQL (thankfully) but it seems to cater to Big Data. For example, I’d worry if you think you’ll have a table that’ll exceed either 10 gig or 1 million records. If it’s less then that then I’d just use MySQL (I would rather use PostgreSQL since it’s faster).
If learning curve is not a factor then I’d definitely go with Angular.js(or ExtJS)/Node.js/Express.js/MySQL(or PostgreSQL) but if you are not familiar with any and have tight deadline then Angular.js(or ExtJS)/PHP/MySQL.