RTV, Permatex, Aviation Form-A-Gasket, The right stuff etc....

Not a valve cover I wouldn't put RTV on a valve cover... But yes at one point or another I've taken all the tin off of my engine... And of course the point you're making is it doesn't come off easy. And it didn't. But I'm not the kind of guy who sticks in a drag strip only Cam and expecting great Street manners out of it... There's always a trade-off.. I'll pay the extra 10 $15 a tube and the extra labor to get the parts off when or if they eventually come off.
I repeat, did I say I don't like leaks...
may as well use JB weld. lol try ultra black, it works real good and comes off easy if needed.
I will never use the right stuff again, used it once on a transmission pan and ruined it when I took it back off for service.