This would not be needed if the stupid Android security model didn't prevent people from running their OWN phone with full rights and doing full backups and restores easily.
Hint: the Android security model isn't for your security, but the security of the data that third-party apps put on YOUR phone - that is, consequently, not truly yours.
Yeah, I would prefer being able to do a back up image of the phone and save it to my computer and then hand it in after doing a factory reset. Then just restore it when I get the phone back. Android sucks in this department compared to Apple.
Also necessary there are very few but apparently some stories that talk about people being hacked because they sent their Android device off for repair or replacement. If ends up in a malicious person's hands and gets used against them some how some way.