I don't think this is as much work as most of the people think. There are nice documentations on who to guarantee reproducible builds, for example on: https://reproducible-builds.org/docs/
Many projects are currently working on or already have a reproducibly build process, e.g.
- Arch Linux
- Tor Browser
However, I don't demand this for Seafile but wanted to know whether the developers of Seafile are generally instrested in reproducible builds and maybe think about that in the future. As stated before, I think this is a big step towards more security for the normal users who don't want to compile from source.