I've been accustomed to grades for my whole life at this point, and I'm not a fan of the new TOK system. I feel like if I do an assignment to the best of my abilities and I do another assignment that's crap, they should not get the same grade.
Devaluing the "100" is an interesting concept still, though. I see that as a student, a lot of times, we are more focused on the grade than understanding what we are learning (exclude "IBDP" because if don't understand we won't get the grade). Previously, I wasn't sure that was inherently bad - I'm still not convinced that it's completely bad.
If you work to get the grade "100" , by whatever means, whether it be just memorizing concepts, applying common sense, or being a strategic guesser.. then did you not still earn the grade? In contrast, on a deeper level I do understand the point of "no grades" is to encourage you to learn the concepts and connect with them for your own personal knowledge.
The problem within that system is that not every student (probably not even most from what I have seen) care about the often absurd (seemingly, maybe not) topics that we learn about in school enough to genuinely unpack them and apply them to our lives.
Even still, because we are IB, and we expected to do this, I think the system is okay for TOK because it forces and encourages interpersonal learning.