If the Bixby button on your Samsung Galaxy phone doesn't get much use, you might prefer to make it open another app. Samsung noted the remapping option when it revealed the S10 lineup this week, but if you have a slightly older Galaxy phone (namely, Note 9, S9, Note 8 or S8), you can customize the button too if your device is running Android Pie.
Samsung will enable the Bixby Key Customization feature with an upcoming software update. You'll be able to open a specific app or run a quick command with a single or double press, and the other method will still activate Bixby.
While there have been workarounds to reassign the button, this is a straightforward, official way to make it more useful. If you're feeling cheeky, you might even remap it to open Google Assistant or Alexa if you prefer those to Samsung's own assistant.