I think the idea is that the heat output of the battery (about 1.5kW) may have made the difference between the astronauts surviving and not since they had no ot

I think the idea is that the heat output of the battery (about 1.5kW) may have made the difference between the astronauts surviving and not since they had no other heat source available - the LEM heaters were all shut down to conserve power after the explosion. Clearly the plutonium heat output was never intended to heat the LEM during ordinary operation, since not all missions carried such experimental apparatus - presumably had the mission gone to plan the normal LEM heaters would have run on a lower duty cycle to compensate for the extra heat input from the plutonium cargo. I agree that it's a badly written article that doesn't actually follow through on the title, so the above is purely guesswork.