As we see in this case, the (likely) person in this case was actually found from the relatively small number of people who fit this criteria, so police were (likely) right to suspect these people.
The issue is not who the police may or may not suspect. it is about reasonable expectation of privacy. If they had obtained this exact same list of people who were near that bank for that time by a means that did not violate their reasonable expectation of privacy, then the evidence couldn't be challenged on that basis.
I’m saying that practically, being within a radius as the bird flies does not make you functionally “within the area” when there’s a huge z axis in a city.
When someone robs the retail of the ground floor of a high rise, there are many people who were right on top of the crime scene measured by lat/lon but were actually 10 minutes away by foot, hundreds of feet away in actual distance, and in no way aware it was even happening.
Two weeks of no leads and that no is gonna start looking an awful lot like a yes.
The system does not care about prosecuting criminals. It cares about prosecuting people for crimes. While it may prefer to prosecute criminals for their specific crimes that is by no means a hard requirement.
A one hour period and 150 meter radius of a bank surrounded by high-rises and public transit? no.