I’m not sure how much of a safety issue it is, or how much it improves performance in an objective, measurable way—besides on fast uphill sprints, where foot retention definitely makes a difference by allowing you to pull up at the back of the crank’s circle.
In my own experience, clipless > straps > platforms, by a wide margin. I feel they’ve helped me more than any other upgrade, and I would recommend them over anything else in terms of benefit per dollar spent, except maybe wheels and tires if you’re rolling on something really heavy.
When I just want to cruise around at a casual pace, any pedals will do. If I’m on any kind of serious, focused ride, I wouldn’t consider going without retention.