Using the on screen shutter button to activate burst was problematic unless the user looked at the screen to touch the button and intentionally slid the button down to burst instead of accidentally just long pressing which activated video or as is still easily done, missed the shutter button and inadvertently slid the camera to another mode.
If using the on-screen button was problematic, then it shouldn't do anything at all. Instead, Samsung changed a setting with no way to change it back and convinced a sizable group of customers that the app is broken. At least if it did nothing I wouldn't have loads of 2s long videos as I've tried to figure out how to get burst shots.
The volume button is awkward to use on an S9+ and as such, I've only ever used it for zooming. Changing a fundamental interaction in a fundamental app is frustrating. Years of muscle memory needs to be retrained with no benefit in return. Moreover, the new action doesn't even make sense. If I want to take a video, I'll switch to video mode.
