To use Smart Crop, you should be using dynamicmedia run mode(i.e. dynamicmedia or dynamicmedia_scene7) on your AEM with cloud-config updated with DM account setting. In case these conditions met and you still don't see Smart Crop renditions than kindly check the Image profile you've created. Does it have the Smart Crop selected? Here is an example which you can compare:
Smart Crop Image Profile Example
If for some reason it still doesn't show the option with the above settings in place, I recommend opening a support ticket with us for further investigation.
AEM Mobile is a totally different product used to build content-rich hybrid apps and stands separate from AEM.
Regarding Smart Crop, its a Dynamic Media feature and is available with dynamicmedia or dynamicmedia_scene7 runmodes, however this also requires the Dynamic Media to be configured in Cloud Services. For more details will recommend to post your query above community.