The main advantage to having this data yourself rather than being held by a third party is that you have a chance to push back if you have it yourself.
If you get a subpoena that you believe is overly broad, you can take the matter before a judge and argue your case. As I understand it, this can be quite effective in narrowing the scope. It's not perfect, of course, but it's better than having no say whatsoever.
Subpoena you have time to fight but if they get a warrant you can only challenge it post execution. Would you only get subpoenas if you retained the data?
But, in general, if you're getting a subpoena it's because you are a bystander in an investigation, and if you're getting a warrant, it's because you are a target of an investigation. So a subpoena offers a bit more protection for you and is easier to push back against.
You can only fight a warrant after it's been executed (at least, mostly), but fighting it after the fact isn't nothing. If you win, the property seized must be returned, data collected must be deleted, and none of it can be used in court.
In theory you should be getting a subpoena for your local storage. Also I'm not sure just deleting the data is really a remedy here since a) there's a good chance people already viewed the recordings and that can't be simply undone so the privacy violation still exists and b) were there to be evidence of some other crime on your interior tapes we know police et al have ways like parallel construction to hide constitutionally questionable searches from making it to court.
A is really my core objection here, the privacy violation of gathering all the camera's data is essentially unresolvable, someone will have at least looked at the footage and at best determined the camera is an interior camera and stopped reviewing it. Personally all my cameras are outward facing (though one is a ptz that could look into the office) and I have only local storage of the video. My other option would be to make an automation that deafens and turns any PTZ camera to the wall unless my alarm system is set to away.
Yes, I understand and am very sympathetic to what you're saying here. There is a real privacy violation involved.
But I don't think it's a real moral conundrum. As I said elsewhere, I think that if we as a society want to have police that can effectively investigate crime, they also need to have some invasive powers. And I think we do want to have such police, because the alternative is much worse.
The reality is that there is no such thing as an absolute right in pretty much anything, because it's rather common that exercising one right can infringe on a different right. So it's all necessarily about balance and compromise.
If you get a subpoena that you believe is overly broad, you can take the matter before a judge and argue your case. As I understand it, this can be quite effective in narrowing the scope. It's not perfect, of course, but it's better than having no say whatsoever.