The reason you can’t usually hear valve train wear is that the valve train shouldn’t wear, what wears is the actual valve itself, it wears into its seat meaning as it wears the valve clearance goes away, a valve train only makes sound when there is clearance, so as the valve wears the clearance goes away, the problem with tight valves is that they eventually get held slightly open and the resultant high temperature air that leaks
past burns the valve and it will no longer seal well.
Almost all valves are adjusted cold, in theory the clearance you establish when cold mostly goes away when the engine is hot and running hard.
Way back in the day of push rod racing
motors, people would stop after a hot lap and as quickly as they could adjust the lash to zero, in theory they were then getting just a touch more lift
and airflow and HP.
Most likely didn’t really matter but in racing
people will try for any tiny gain they can get.