Damned good advice! Even outboards that have the fuel tank inboard need to heed this advice. My Ranger Bass Boat developed a leak in the water separator filter under the cover during a tourney once, filling the bilge with gasoline.the difference in marine grade electronic components (primarily speaking of ignition parts) is that they are designed to eliminate/minimize the possibility of a spark in the engine compartment. Inboards are highly susceptible to ignition of gas fumes due to the inability of the engine compartment to self evacuate the fumes. It's worth the extra cost of those parts.
Never ever start the engine until you have ran the exhaust fan(s) for a few minutes to ensure evacuation of any fumes in the engine compartment. Also, if the engine is carborated you will notice the breather doesn't look like the one on your old Chevy pickup. This is for the same reason. It's constructed to minimize the possibility of an engine compartment fire. I have always highly recommended people open the engine compartment for the initial cranking for any outing. This is when the engine is cold, has sat a while and is most likely to not fire up immediately and possibly flood out filling the compartment with fumes.
I know I sound overly cautious about this but have on a couple occasions had to deal with the aftermath of an engine compartment explosion on the water. It's not good for anyone involved and the loss of the boat as it burns to the waterline is the very least of the agony.