The Play command serves an important role because "Play QUIET" is the best way to quickly preview large amounts of (short) audio files, which is a big chunk audio work. The waveform seek is needed for longer recordings, where you have hours of material in one file and need to visually find locations of interest.
An ideal workflow would be to have the ability to chain both uses together, where the first step is to quickly start playback of a file with no needed windows or other extras, and the second step would be to (when needed) open a window with waveform seeking to get playback to a desired point in the file.
I want to stress that the thing that is great in DOpus right now is the speed with which the Play command starts playing a file, combined with not having to move your mouse to stop playback or close windows that might have popped up and are now in the way of a drag and drop to your editor etc.
I preview/open hundreds if not thousands of audio files a day, and the difference between playback starting in 2 seconds and 200 milliseconds, or you having to spend an extra click or two to get to the next file is a dealbreaker issue.
The 3rd party media player apps all have varying problems of slow startup times, windows that won't stay in the background, lack of visual seek and little to no file operation possibilities. These are the reasons why DOpus has been the best media player for demanding work, despite not being designed to be one!