My bank offers that sort of deposit. Take a pic of front and back (typically with their app), verify the amount is correct, and POW, it's in my account.
That 5 business day processing thing comes from having to handle the physical cheque. It has to be secured, accounted for, processed (that used to be a mind numbing MANUAL task of reading and keying in EVERYTHING on the cheque), then marked as processed and stored for audit and verification purposes.
Now they're read by machine, processed by machine, photographed for audit/verification, and probably quickly destroyed. But it's still an overhead-intensive task. So by having customers photograph, verify numbers, and retain the things, banks are saving a LOT of time and money. They really should be giving you that 2% and more.