If your insurance company doesn't know about your offences and you have a crash, they could refuse to pay you out. I've seen it happen unfortunately.
I've had a couple of fines but nothing major ie.
"driving without seatbelt" .. pulling belt on as I came out of the carpark
driving through a no-entry sign ... in the backstreets of my suburb
couple of speeding fines
got pulled over the other night doing 95 in a 70 zone but I had no-one in the car with me, and there were no other cars around, so the cops graciously let me off