Honestly, do you look at the justice system in the United States and think "You know the real issue here is that not enough people are being punished"?
I have a family member who was murdered. I have a lot of sympathy for victims of violent crimes like this and a hard time understanding people who want to let the murderers go free, because I know what it's like living under the threat of one who kept a list of who they intended to kill next.
But look at how many people have been unjustly/incorrectly imprisoned for many years in the US, often based on poverty or racism. Would you be willing to jail 5 people for life-without-parole if you're 100% sure ONE of them was the murderer of your family member? What about two people?
So I'm loathe to rule out the use of more accurate ways to pinpoint investigations when the status quo is someone who thinks they saw the person at the scene, when we know how unreliable that is.
That feels like throwing out DNA because there are many explanations of why it might be at a crime scene in favor of good old fashioned witness identification, never mind one is a lot better than the other, even if both of them have been misused terribly at times.
That's why I think we should want the cops to use methods that cause fewer people to get wrongly investigated, because it is a burden. It's true, your phone being too close to a crime scene doesn't make you a criminal, but it's probably a better reason for investigating you than traditional things like "I saw a guy who looked like that at the scene" which has much more frequently caused the harm you cite, and yet it's been a staple of courts longer than any of us have been alive.
That being said, I'm sympathetic to your point here and I'm not advocating for eye witness testimony becoming the only source of truth. If I could somehow know for sure that this would ONLY be used for the worst of violent crimes it would soften my opinion, but I am very sure that the more normalized this sort of dragnet investigation becomes the standard of what "requires" it's use will get lower and lower.
If policing were entirely focused on violent and property crimes many of my opinions might change, but realistically I think we can agree that whatever investigative technique we are talking about will primarily end up being used to prosecute drug crimes, because that is much safer and more profitable for the police. Do you really want to be on a suspect list everytime someone thinks they saw a drug deal somewhere and you happened to be near?