The calculus may be changing w/ the upcoming massive devaluation of Bonvoy. Until recently, however, there were many who considered holding a card w/ a $95USD annual fee to be worthwhile on the basis of the FN certificate alone - without necessarily earning a single point actually using said card (so this discussion has nothing really to do at all w/ points, per se).

Since you yourself earn such a substantial number of points annually, a 35k FN cert is probably not even on your radar. But not everyone here earns a fully self-sustaining number of points similar to your situation. Additionally, consider that some of us own businesses and like to open and maintain accounts under our business banners, leaving us with duplicates where we see value in doing so. Lastly, there were many of us who held one personal and perhaps even one business card in both MR and SPG, which then left is with two to FOUR Marriott cards.

I myself was finally beginning to see value in the 35k certs (up from 25k) and was using them to good effect, and so was sitting on the three Marriott cards I've left open thus far. But now that Marriott has predictably moved the goal post, I'll likely pare that down and find better cards outside of just the lone Brilliant account.

Edit: But I'll do so slowly, as I'm careful about my credit score.