It's all down to preference and what one is accustomed to. Years ago clipless was dominant, and might still be in cross country racing. Flats have seen a resurgence in recent years. I remember big, long arguments over which is better. Both types seem to be common enough now that people don't argue as much, which is a good thing. No harm in trying both, then just roll with whichever you happen to prefer for the terrain that you are riding.
If you are racing, choose based upon which type helps you to win races. If not racing, then just roll with what brings a smile.