In general classic confinement is not required to access files on the system - between home
and perhaps some particular instances of personal-files
and system-files
you should be able to access any required files. Also the ability to access arbitrary files is not itself enough of a reason to be granted classic confinement, a snap must also fit within one of the known categories defined in Process for reviewing classic confinement snaps - can you please review this documentation and if you still feel that classic confinement is required and justified for this snap then please let us know with a detailed description of why. Thanks.