I like using mods; that's the main reason I make them. It takes a lot of time and effort to make any mod, so we modders look for any way to make the process go more quickly.

If modders release the source files (such as the smd text files for survivor model mods), other modders can use the source files to learn from, to improve the mod, or to build another one based on them. It can make the process go much more quickly than trying to decompile or re-create features that can't be decompiled.

Thus, more source files means more (and perhaps better) mods, because it will be easier for people to learn from the source files.

I release the source files to my mods separately from the mod, just to keep the mods clean from any unneeded files. It also keeps everything organized, so people don't have to guess which files are the source files and which are the mod files.