The title says "hard" foul not "flagrant" foul. There is a big difference. A flagrant can escalate, or earn a suspension. A hard foul is just a message. It's got a place in the NBA, particularly the playoffs. If someone is showboating you can give them a hard foul just to remind them this isn't a playground, and they aren't playing chumps.
No, don't undercut the guy, and don't powerslam him, but a good wrap-up never hurt.