so as far as i understand i can make a small and portable field recording rig with this app...lets say scarlett 2i2 + samsung galaxy s3, and few mics...will it work?
Depends on your definition of 'portable' and 'field': the 2i2 is USB bus powered and your S3 won't provide enough juice to power the 2i2 and some phantom powered mics. You wouldn need to put a powered USB hub in between which would make it less portable.
Note that the 2i2 doesn't work for everybody, probably due to this power requirement, so you need to check with the free trial version to see if it works. Let me know how you get on.