Couchbase Number Of Nodes Requirements

Hello All,
We are using couchbase server version 5.1.1 with 4 couchbase nodes.
and we want to give 3 number of replicas to each of the buckets in our couchbase cluster so that means 4 copies.

After googling we found this link and it is saying that for 3 replicas we should have atleast 10 nodes.

And in the last line they are saying that

While there can be variations to this, there are diminishing returns from having more replicas in smaller clusters.

What does this mean, is there any disadvantages of using less then 10 nodes for 3 replicas?

So is it possible to have 4 copies in 4 nodes, will it work or what should be the recommendation?

Thanks in advance

@Ronak_Pandya If you have 4 couchbase nodes then it is better to have one replica. That is our generic recommendation. What is your use case? Is there a reason you want so many copies? Yes, theoretically you can have more replicas but if you have 4 nodes one replica should be fine