SLF aside: If I was in an evacuation situation, there's no way I would leave everything behind. For example, last time I flew I had all my essentials in my jacket pockets - passport, keys, wallet, phone etc. I could have flung open the overhead locker and grabbed my jacket in 3 seconds, literally. Just grabbed it and went, not put it on till I was outside.
You might say that those three seconds could be the difference between life and death, but in the wider context of getting everyone out of the plane, it's probably not. If it comes down to three seconds, my goose is probably cooked already. Weigh that against the hassle and expense of replacing those essentials, and it's a chance I would take. I imagine women feel the same about their handbags, and would grab them too. But I agree that suitcases should be left behind - that's too much. Small & quick can be done safely.