So I’m guessing you’re a Revolut user then 
I’m a little bit biased here because in principle, I think settings are a bad thing - they create complexity, hide functionality & make support more difficult.
I can see the appeal of those settings, it makes you feel like you have more control but…
Contactless - as far as I know, the contactless card fraud that people worry about is low. And assuming that you meet the rest of Monzo’s terms, they will be liable for fraudulent use of the card.
Cash withdrawals - this seems like a strange one to me. Unless someone sees your PIN and steals your card (again, unlikely) I’m not sure how you’d be at risk. But maybe I’m missing something?
Online payments - in my opinion, this is a bad idea because merchants like Amazon will only take your payment when they ship your order. Obviously this setting would block that.
So ultimately, I think these settings are more placebo than useful & I can’t see myself using them. But maybe others will disagree!