I'm not familiar with this library, how does `text("(now())")` evaluate and why there are extra parentheses? And should that be a lambda expression as well, so that `create_date` isn't just the timestamp when the python process was started?
As to the extra parentheses: I bet that's a force-of-habit thing to prevent potential issues. For example, it seems Sqlite requires them for exactly this kind of default definition[1]. It could also read to nasty bugs when the lack of parentheses in the resulting SQL could result in a different parse than expected[2]. Adding them just-to-be-safe isn't the worst thing to do.
[0]: https://docs.sqlalchemy.org/en/13/core/metadata.html