While the instrument rating may get one through some events, it is not a
guarantee. In a single engine piston aircraft without weather
avoidance equipment, one runs the risk of flying into embedded cells.
ATC may or may not keep you updated on weather along your route of
flight, it's not their primary function and is one of those as time
permits things.
I have been instrument rated since 1986, but I won't challenge the
weather gods knowing that there is convective activity along my route.
Better to fly below the clouds and see the weather with the Mark I
Eyeball than fly blindly in the soup.