It’s probably psychological but knowing you can shove a leg out, dab a foot down or simply bail makes me attack stuff with more purpose than I did riding clipless (I’d had a few spills made worse by clipless in the past).
But it’s not like you can’t do that with SPDs – just unclip!
A year ago I’d have said “I’ve never, ever had a crash and experienced the horror of staying clipped in all the way down”. Now I have, a couple of times, including one episode where my foot came out my shoe, which stayed clipped in! But it’s still sufficiently rare that I don’t really worry about it.
I find not wearing leg armour with flats is a guaranteed way of making my leg come into contact with them!