Not just the Galaxy S10: Bixby key customization will soon spread to other Samsung phones

But after almost two years of stubborn insistence on Samsung's part to either block or complicate any attempts at modifying the behavior of the hardware key on the Galaxy S8, Note 8, S9, and Note 9 in any way, the company is finally listening to its annoyed users, giving potential Galaxy S10 buyers one more reason to pull the trigger. Even better, we now have confirmation via the official Samsung Newsroom that the so-called Bixby Key Customization feature will indeed expand to "previously released Bixby-enabled flagship smartphones"... at some point.
Instead, Samsung will offer you the choice between single and double pressing your phone's side-mounted key to launch Bixby, while the other option can be used for a "Quick command" or to open any app you want. Basically, you can program the button to summon your Google Assistant with a single press (just a random example), relegating Bixby to double press initiation.