This simple scheme allows all members including replicas to serve read-after-write consistency and penalizes the write op that happened. That write op wont be acknowledged to the caller until it has been applied everywhere.
There are no fault tolerance issues here btw. If any replica fails, as long as quorum was reached, the repair procedure will ensure that write will be eventually applied to all replicas. If the quorum itself could not been reached then the write is lost anyways and is no different than the typical case of reading just from the leader.
However, for the sake of discussion, this is an interesting point on the design spectrum! A scheme that provides read-your-writes but not monotonic reads is essentially what you would get if you took global tables as described in this blog post, but then never had read-only transactions commit-wait. It's a trade-off we considered early in the design of this work and one that we may consider exposing in the future for select use cases. Here's the relevant section of the original design proposal, if you're interested: https://github.com/cockroachdb/cockroach/blob/master/docs/RF....
That removes all the fault tolerance. What do you do if you never get the acknowledgement from all replicas?
So it can tolerate up to N/2 failures just like other consensus system. Because this is basically Raft.