It's the same as the source with the added advantage of a database to keep up with it.
If you have dependencies with A.rpm , B.rpm, and C.rpm where A needs B and C and you install them from source, then a problem will arise if you replace some files in B or C, or delete them. A will not work properly without the needed files.
It's the exact same thing.
99% of what's on my laptop here is built from source targeted for this system, using rpmbuild.
Basically to install source A which needs source B and C you would do this..
unpack the source packages
Now if your building rpms..
unpack the same source packages
follow this proceedure for all three of them
The result is the same except for with the rpm you have a database that keeps up with what needs what. Not perfect but way better than just trying to get lucky.
The bottom line is you need some form of package management or you will probably run into trouble and then you will be pulling hair to figure out what to do.
Many distros are using package management in some form or the other because it's mandatory to have something to control dependencies.