Because it wasn’t a throwaway anymore. His plan was to take over magical Britain as Voldemort, and have both the ‘true’ respect that comes from fear of what he can do to people and the pleasure of killing idiots whenever he wants. (And possibly to exterminate the Muggle world, but first things first.)
Why did Tom Riddle allow his true identity to be tied to his throwaway villain persona?
Because it wasn’t a throwaway anymore. His plan was to take over magical Britain as Voldemort, and have both the ‘true’ respect that comes from fear of what he can do to people and the pleasure of killing idiots whenever he wants. (And possibly to exterminate the Muggle world, but first things first.)