Valve cover - bolts are studs

I tried the 'T' handle type as a teenager, I found that they would vibrate loose over time.

On cars with adjustable rocker arms, short studs & nuts can be handy.
Oddly enough, for the first time that happened on the wife’s car. The only difference I found in the old vs new T handles I’m using is the stud itself wasn’t a standard SAE but metric or ill machined stud. Yup! Very annoyed at this but so far, the jury is out to its actual worthiness. I can cut my own studs from a long threaded bar stock I have.
Again, just an annoyance.