The importance of SET NOCOUNT ON in the all the user defined SPs is very important to get good performance.
False: If SET NOCOUNT ON is executed inside of every sproc with every execution you gain NOTHING and loose performance.
If you want a true performance gain and get the added benefit of not having an extra record set (message) returned to the calling application then SET NOCOUNT at the connection level.
You can also set this as a default connection setting for all server connections and let the user app enable row counts as needed for proper code execution and performance.
Running any SET command during the execution of every user sproc on a server only increases the number of cores needed to support SQL execution not reduce it. You might see a small performance gain in application code with 1 to 10 users connecting. That would disappear once you connections started reaching the thousands and you TPS is over 500.