Integration is poor. Some tooling is not aware of it and will diff or show the pointer file instead, such as Git hosting platforms. It is also easy to end in situation where the pointer file hasn't been smudged, and Git might not report a change and might make it hard to find what is and isn't smudged... at least that has been my experience when dealing with large repositories where I sometimes want to only pull large files in specific folders.
I think either you get super integrated but restricted ecosystem (eg. you can use darke files but then darke files is all you can use) or you build on top of an established protocol and get something maximally compatible (any git server) but some software will ignore the extra bits.
