> or are there still good reasons for using it in a new project in 2025
it's not clear there ever was. Most of the big users I'm aware of, like Stripe, don't seem to have needed it and regretted the decision. Big data didn't become a thing in the way people expected[0]. If you really did need the scalability of Mongo you'd choose a NewSql database like TiDB[1].
a) Big data is more than just the size of the data. It's about how you treat that data i.e. instead of doing expensive and brittle up-front RDBMS modelling you instead dump it all into a data lake and figure out how to handle the data at run-time. And it is still the standard pattern in almost all companies today.
b) Nobody was choosing MongoDB solely for performance. If it was you would choose some in-memory K/V store. It was about it being the only well supported document store that was also fast and scalable.
That's not how software works. In my experience using mongodb just means that now every single bug in the code creates messed up data for a few months/years and then when that data pops up the software crashes :D
it's not clear there ever was. Most of the big users I'm aware of, like Stripe, don't seem to have needed it and regretted the decision. Big data didn't become a thing in the way people expected[0]. If you really did need the scalability of Mongo you'd choose a NewSql database like TiDB[1].
[0] https://motherduck.com/blog/big-data-is-dead/ [1] https://docs.pingcap.com/