If you are medicating, those levels stay more consistent and reliable with a cycled. Ammonia will cause stress, so both the harm of ammonia itself and the stress caused is reduced. It's cheaper, you're not dumping 3-5 gallons of salt water every day, and meds if that is your qt procedure. And keeping cycled media is super easy. If your current display doesn't allow for added media then uncycled will work, but more attention must be paid.
I'm planning a large fish haul soon for both fresh and salt water. I am getting 3 tanks ready and have cycled media. those are for fish going in tanks with current stocking. I am setting one up from zero which will not have qt'd livestock but will get cycled media and bacteria added. If something there goes wrong, I can treat the whole tank as it will likely be a mbuna tank.