When you play a tight points limit, every point counts (der - I know, I know). So you need to do an analysis of what does super heavy bring. Several things spring out:

1. SH damage table - no immobilised, no Weapon destroyed. They must absolutely positively kill every HP.

2. Thunderblitz/stomp. The former is situational but amusing. The latter highly useful.

3. A big nasty weapon. Or 2.

So I personally weigh all that up. This is how I came to the conclusion about Typhon at lower points - in fact my purchase was based on the old 1500pt format for Throne of Skulls - I wanted something to do 1,2 and 3 above and at 350 base, nothing else competes. AV14 all around and ceramite armour for 20 points - someone will need D or serious Lascannon quantities to damage that. Pre-grav of course.

But I think there is a sweet spot where the SH won't make its points back unless you are careful - it can only hold 1 objective, and even separate targetting wont allow you to swamp horde armies.

I think this is why IG Malcadors etc suffer. A lot easier to pen than a AV14 box (especially a ceramite one) so can be brought down without as much effort. Similarly people are used to countering IK - 13/13/12 can be dealt with with anti LR tactics from 4th ed.

Just some further ramblings whilst the D pounding is ongoing.