OK, here's my SERIOUS reply. For any kind of distance, I wear everything. Cycleport suit is top of the line IMO. I do have a good sturdy leather jacket that's great in the winter--such as we get here--and I wear it with all the rest of the gear.
OTOH, I admit, there are some compromises. For example, for just a run in town, errands, etc., I'll have on a pair of riding "jeans"-type pants with leather/kevlar inserts in the knees and hip/butt area. I suppose they'd help--some--if they had to. In the worst of the heat, I wear a lighter-weight mesh jacket for short rides, too. And I wear a modular ("flip-up") helmet, that many will swear is a death trap for your head. I don't believe that, myself, and it's MUCH more comfortable to ride in--or stop in, especially in the heat. I don't have $200 super-armored gloves, or the very last word in boots. Somebody sells jackets with air bags that inflate instantly in a crash. I don't have one of those either.
But the one time I crashed, I was wearing all my gear. Almost. Very hot day in Montana, heading to NAFO in '08. I'd lost my mesh gloves at a camping stop. Riding in everything BUT my hot leather gloves when I took my rock dive. Worst injuries? My hands, what else? Both all scraped and cut up, one knuckle still oddly lumpy. Only other injuries were bruises. Lots of bruises. Lesson learned.
So you decide how much of a risk you want to take and you live with the results. Like whether to ride a motorcycle, how fast you want to go, how much safety you want to try to guarantee. Good luck with the choice and the results.