For contacts I kinda get it.
You could have eye conditions that make you unsuitable to use contacts.
For glasses, its absolute bullshit.
An “incorrect” lens placed on the exterior of your face will not harm you (other than making you a bit dizzy).
Purism is sketchy btw:
https://www.youtube.com/watch?v=wKegmu0V75s
https://www.youtube.com/watch?v=-IjUryQOlgk
(Louis Rossman videos explaining how a customer was denied a refund for a “pre-order” and then they tried to coerce Louis to take down the video.)
Edit: typo