There are different approaches and it all comes down to who you trust. I don't think there's universal answer. If you have money, find image provider who's serious about security and hopefully they'll provide patches images quickly. Otherwise using Debian packages is a good default I think.
Honestly I don't even understand why so many docker images prefer to build software from sources, rather than just installing them from debian repositories.
> I don't even understand why so many docker images prefer to build software from sources, rather than just installing them from debian repositories
Because Debian uses older relases and a lot of custom patches. One example: Nodejs still doesn't have Typescript support in the Debian packages.
Distribution packages vs. official build from source has both pros and cons.