I don't like being devil's advocate on this because I am strongly against the invasion of privacy at that point in the investigation, but without that data, they'd just take a bit longer to have identified the members of the insurrection. There's varying degrees of data you can glean from cellular networks as well, right down to "it was definitely this person, the phone logs show a FaceID unlock at X time" and that action can be inferred by network logs, all information that carriers have retained for over two decades.

What it does become is a data point in an evidential submission that can strengthen a case that could otherwise be argued back as a bit flaky. It's similar to DNA evidence in that it's not actually 100% reliable nor is the data handled forensically at every stage of collection, but it's treated as if it is.

I think it's weighted too heavily in evidence and should not be used as a fine-toothed comb to sweep for "evidence" when it can be so easily tainted or faked. At the same time, I'd love to see the current members of the pushback against ICE using this data fallacy against future prosecutions. "Yeah, I was at home, look" and actually it's just a replay of a touch or face ID login running from a packaged emulator, or whatever signature activities meet the evidential requirement.