The reason I never bought this in the past is because I won't turn over any computer with my data on it.
Let's say I had an issue with my MBP and was going to use the warranty or Apple Care, what would happen if I swapped out my SSD with data on it for another Apple SSD?
They might claim it was no longer the original MBP, but I could counter with, "Sorry, but my original SSD failed and so I replaced it."
Would that work? Especially if the warranty issue was on something like a bad monitor?
If you have AppleCare, then if the original SSD failed, you would have brought it to Apple for replacement - failure of major components is one of the key reasons to have AppleCare. So, no, Apple wouldn't consider, "It failed so I replaced it" to be a convincing or logical explanation. You might as well say, "I don't trust you with my data, so I swapped it out." Whatever reason you give, it doesn't matter - you've confessed to making an unauthorized repair. By doing that, you may have voided the warranty.
The thing is, how does Apple know that the display was bad before you swapped the SSD? The display could have gone bad because you screwed up while swapping the SSD (static discharge, for example).
You may also have made it impossible to perform a proper diagnosis. Problems with computers are often due to what's on the HDD/SSD - erase it or replace it, and there may be no point to bringing the thing in for repair.
If you can perform an undetectable repair, great. If you're that good, then don't waste money on AppleCare, just bookmark ifixit.com
The thing about repair shops (or seeing a physician) is that the customer/patient is not expected to know what's wrong. "It doesn't work when I turn it on." "It hurts when I move my arm this way." You describe the symptoms, and let the expert perform the diagnosis.
Apple will not repair damage done during the course of an unauthorized repair... well, they might, but they'll charge you for it, it won't be covered by AppleCare. They may also insist that a Mac be restored to its factory configuration before performing service on it - the warranty covers the factory configuration, not your customizations. They'll fix defects in
their workmanship, and
their materials, not yours.
As has already been noted, there are less invasive methods for protecting your data. Your data should all be in your user login account(s). Copy those, and leave the rest of the SSD's contents intact. Create a new, clean Admin user account so that Apple has something to work with, and delete your User account(s) from the machine. Restore them to the machine after Apple is done.