Security: with local storage it's on you to make sure that your NAS or whatever is constantly up-to-date with security patches. And that's assuming your NAS provider keeps providing patches. It's on you to do all necessary monitoring for intrusion detection etc.
Reliability: with local storage it's on you to keep backups, make sure those backups work, replace failing drives, don't accidentally wipe the drive, and make sure you have distribution across geographies. Good luck with that.
Cost: sure, local wins here.
If systems administration is your fun hobby, or you are incredibly cost-sensitive due to large scale, by all means manage storage locally. Otherwise pay professionals to do it.
Reliability: with local storage it's on you to keep backups, make sure those backups work, replace failing drives, don't accidentally wipe the drive, and make sure you have distribution across geographies. Good luck with that.
Cost: sure, local wins here.
If systems administration is your fun hobby, or you are incredibly cost-sensitive due to large scale, by all means manage storage locally. Otherwise pay professionals to do it.