Most previous court cases involving encrypted devices have required substantial proof that the encrypted device contained incriminating evidence. To be clear "you sent this illegal thing from your house" levels of evidence.
It mostly seems inept, if you are going to push to expand your powers you do it on strong cases where you know what happened. Doing it on weak cases like this gives a judge an opportunity to shut down that without giving you a chance of a meaningful conviction and without that you won't get any benefits...