After an injury, you may want to get an MRI to help you recover and determine best course of action. If an MRI cost a million dollars, or a single MRI scan took an entire day (which means every machine within driving distance will be booked years in advance or will be reserved for only the most critical cases), you won't benefit from an MRI image.

"Megabytes per second per dollar" may not be the optimal way to phrase this, but cost and efficiency are a real concern.