Cost of keeping all data (up to +100%). If they dont change, no point of really versioning them. Backup of those is simple either, whatever syncing software (incremental).

Docs that often change, its completly different story. I love VCS like features where I can slam 'dot status' to see whats going on, commit when I feel I need snapshot, sync to whatever device I want. And because I run DVFS I dont even bother with backups because I have multiple copies of repo with entire history.