globc malloc works reasonably well if threads are not used (nginx and postgres are examples of apps which don’t rely on threads), but if an app uses many threads on multi core CPU shortcomings of glibc malloc (or advantages of jemalloc) become more obvious, especially if you use some LTS Linux distro with an old glibc.

For databases maybe.

However, most programs do not need to allocate so much memory, so frequently that an allocator become an issue.