> Police now know they cannot use this method in the future, so suppressing the evidence in this particular case does not disincentivize anything, as long as its made clear that it cannot be done in the future.

It disincentivizes constitutional crapshoots where they throw stuff at the wall and see what sticks. It incentivizes using already known-good techniques where possible.

“This method” is also frequently scoped very narrowly. Next time they can get the data from a slightly different place, and it’s suddenly a new case. Or they filter the time or device info slightly differently. There are a bajillion permutations one could argue about in good faith.