A warrant is better than no warrant, but:

A warrant requirement is not a reasonable bandaid to consider allowing mass surveillance. There should be no mass surveillance, only targeted surveillance.

A warrant requirement makes sense for something like the locations of customers on cellular networks, because, although it should be improved, it's been built into the tech.

When you make the optional choice to create mass surveillance, safeguards do not make it acceptable.

Plenty of places have very low crime without mass surveillance.