The Smart feature has alot of error codes to present to you at anytime. If your supplier starts acting up.....stop them in their tracks and give them a random smart code. They will shut up and summerize an error report. For example......error code 203 means ECC errors. After giving the supplier that code what else can they say to you? The supplier works for you under contract. You don't have time to defrag, do this and do that. Make them work.
You obviously live on a different planet? In Europe you run the manufacturer's diagnostics first. This will read any SMART logs and will conduct other tests that SMART doesn't get near. It also checks to see if the item is still under warranty.

It will then produce an error code that the manufacturer knows, understands and trusts............ and automagically provide an RTB document that you just send with the defective drive.

After giving the supplier that code what else can they say to you?
They will tell you to run their diagnostics

This is particularly true of small/medium businesses, SOHO and private domestic users who have no special relationship with their suppliers and whose only contractual rights are those granted by the manufacturer's warranty and local commercial law.

Please remember that Europe is made up of a number of countries who all speak different languages, and that long distance telephone calls are obscenely expensive by US standards. The manufacturers diagnostics are the way to go to get a speedy resolution, or any resolution at all.

Another thing, is that here OEMs typically supply a system with a 1 year warranty. HDDs frequently have a 3 year warranty. Strictly speaking, your legal rights are 1 year for ALL components, but the HDD manufacturer doesn't check that, if they get their own RTB document..........they just send you a replacement.............I have pulled that stunt more than once
You certainly don't want to make contact with them other than through their RTB system because you will be asked what machine it was running in and that would be game over.

Legally your contract is with the OEM and their contract is with the HDD supplier.

This is how you get things done and make people jump. That code saved your workload and made you look good to the boss when the customers are complaining to him/her. You right....it is predictive in this case.
SMART is predictive and premptive. You are seriously suggesting you would tell your boss that a drive you were responsible for had been giving SMART errors and you had done nothing about it? That sounds distinctly career limiting to me

Because the manufacturer's software is analytical and diagnostic there is no suggestion that you might have been asleep on your watch

Anyways, how many end users have the faintest idea what SMART is? They bring the drive to you when it is already playing up, and the SMART data are an irrelevancy in the past. Show them the manufacturer's RTB voucher and they are happy because they are going to get a replacement, or the diagnostics log and they know that they are going to have to buy one because it is out of warranty.