The only way to create a compelling product is to use it regularly. It doesn’t matter how good the specs or the client feedback or the testing is, you, the person making the thing, must use it. Daily if possible, regularly if not.
You will catch things that you would never know about. Little hiccups and annoyances. Things that make no sense after daily usage but made perfect sense beforehand. The only way to know about those things is to use what you make.