Drives intended to go in RAID arrays have different firmware and handle errors differently.
They may also get different testing. I worked for a telecom equipment vendor and there were specific drives that had been tested for behaviour under high/low temperatures, high/low humidity, vibration, etc.
If you're a big enough company then drive manufacturers will actually work with you to resolve drive firmware issues and/or answer questions about specific behaviours on their enterprise drives.
Lastly, at least in the SSD space at least some of the "Enterprise" drives have much better handling of power outages, with sufficient capacitors to handle writing out data.
It's not always worth buying "enterprise", but sometimes it makes sense.