I've used Robosats before but I don't have the patience to complete orders manually with a human instead of an automated market maker. There have been times when I've had the best order on Robosats by premium and it still goes unfilled for like 4h+. On an exchange a buy order takes less than a second. The difference between my order completes in several days vs instantaneously is too big.

Also I withdraw all my bitcoin after buying them, so exchange failure is not a risk I'm worried about.