I think it has the same sense as including the source code to the model.
I want the user to get what they want from the model, but I wouldn’t want to loose the model either. I also do not want to waste file space, and bandwidth.
This is pretty confusing to understand.
For development, yes, keep the .blend file in source control. This is your raw asset.
For the game that you’d ship publicly, I’m not sure how Unity packages it, but internally, Unity exports the .blend file to a .FBX file.
.blend files are larger than FBX files, given the extra Blender-specific information, and probably different storage structures too.
So, to summarize, what I do is as above; In development, store .blend files in source control, but for game builds, use FBX files that were exported from the .blend files. This keeps all your edited data intact in the .blend files, and providing the smallest data footprint for the end user with the FBX.
I think we need more information… Is this a question about an asset store model or is this for your own use?