This isn't a necessarily me arguing with you, just some thoughts.

• We have already seen multiple instances of law enforcement misusing technology (Flock, for example) with or without a warrent. Before these technologies, it was a lot less convenient to do this.
• It is illegal to open someone else's mail without permission. I think this is the case in a lot of places? We don't have a similar digital concept (probably because the post office is a government service and digital stuff is corporate).
• Before this technological era, if the police wanted to wiretap someone or follow them, they wouldn't immediately have access to every single thing theyve said or done before that point in time. I think that is also quite important if we're comparing/contrasting