Yes, I kept freshwater for a few years so it seemed odd not to use a filter when I moved to salt, but my LFS
guy who's been keeping salt since 1977 said learn from my mistakes, don't use a filter. So I went with his recommendations and I've never looked back. He always says there are no experts in this hobby, we are all learning everyday. There are no right and wrong ways, just the way you choose to go. If people want sand and a filter then that's personal choice. All I'm trying to point out is that you don't NEED sand and a filter, just rock, skimmer, flow, lights and stable parameters. Then watch your tank flourish.