In a few years (2-5) the headsets will begin to break for whatever reason. When warranties expire people will start going on the Internet watching movies about disassembling those products. That's when it will start being useful.
The same happened to me with my Galaxy S3, I unscrewed my phone to find the cause of my problem and it turns out I have to replace the whole motherboard on my phone. Now I know better how to replace it (plus the YT videos will be helpful).
The information in this article tells me that it's much better to buy the Vive than the Rift when it comes to repairing it.
It's the same when it comes to smartphones - my S3 and one of the newer ones, like the S7. My S3 has a load of screws so I can open it much easier. The S7 has lots of glued parts so I wouldn't be so confident about messing with its innards.
I do consider this part of a product when it comes to buying something. And that's why it can be relevant to some people.