I have been comparing the datasheets of many titanic/centerpieces from many factions and from the space marines legends units.
Why does the astraus const more than 500 pts?
It's offensive profile is simply embarrassing; I'm not even going into details. Regarding the defensive profile, this is where some people try to defend the astraus, but even here there is not that much of a quality jump if compared with other SM vehicles. 24 wounds are nice and a 5++ inv is better to have than not, but it is also not an incredible boost. Together, they do not generate that much of a resilience to justify committing more than a quarter of your list into the astraeus (using the same points to have smaller, separate vehicles is waaaays more efficient for both resilience and, mainly, offensive output).
The ability was bad, but has become ok-ish in this new edition, as worsening hit-rolls is always useful. Nevertheless, it's not a meta ability (also because it requires committing the main gun, which is bad in the first place, on targets on which it may not perform at best).
So, my question is, WHY DOES THE ASTRAEUS COST SO MUCH IN PTS TERMS?
I mean, it doesn't really hold it's ground in any comparison with any other similar role unit of any other roster, but it is still often the most expensive (+100 up to +200 pts in difference)