Would be interesting to get a comprehensive list of what is and isn't available without a warrant from a judge. For example...

"Police can get phone records without a warrant thanks to a 1979 Supreme Court case, Smith v. Maryland, which found that the Constitution's Fourth Amendment protection against unreasonable search and seizure doesn't apply to a list of phone numbers. The Electronic Communications Privacy Act (ECPA) — a 1986 law that underpins much of how the government can get digital data — requires providers to allow access to real-time data with a court order and historical data with a subpoena."

https://www.propublica.org/special/no-warrant-no-problem-how...

A formal statement of "we want this information and may be using it." There is a lot of paperwork that government goes through to document how it gets its information. Getting the information via warrant shows that this was asked for and received in a legal manner (rather than someone dropping some illegally obtained data on a website - even if there are legal channels to get it).

I think it is important to note, that thought "lots of stuff" may may be available to the government without a warrant, "lots of stuff" may not be usable in court without a warrant. So - search warrant is often needed...

They can't get the content of communications w/o a warrant is the reason. They need that for legal action.

However, the stuff they can get without a warrant is enough people /do/ freak out if its applied in a manner they understand.