On Windows, VLC's playback speed can be discovered on status bar, but the Mac version doesn't have a status bar. Where should I go to see the current playback speed?
You can also setup the OnScreenDisplay which will display playback speed changes, step forwards, step backwards and other changes during playback.
Go to VLC -> Preferences -> Subtitles/OSD -> Enable OSD.
Save settings and quit the vlc app so settings get applied.