Because only Order-of-the-Phoenix types used Voldemort's name:
“Exactly! You’ve got to give them credit, it makes sense. It was
only people who were serious about standing up to him, like Dumbledore, who ever dared use it. Now they’ve put a Taboo on it, anyone who says it is trackable — quick-and-easy way to find Order members!
Unlike the name "Harry ...
I believe "Great Merlin's Beard!" was used by Dr Bombay in "Bewitched". So much of Harry Potter came from that show - witches walking through walls, mortals and witches married, spells being thrown like wand-fighting in a position suitable for the katana, etc.