If it was a semi-circle it would be difficult to prove any intention unless there was some form of indication to show an orientation . However it does look from the pic there is a possible indication ,the straight line of rocks , if they point to an auspicious astronomical event like a a solstice it's pretty good evidence for such an interest and intention to be attributed to the builders . Of course it's not guess work but not difficult either .Sadly we can't confirm it as we don't know where it is and the precise orientation of the rocks . Not unlikely that there was an interest in solstices etc at such a late period .
Done a bit more looking around and the scientific work on it being some sort of astrolab appears weak.
I'd always thought (rightly or wrongly) that the emergence of farming and transition from roaming hunter gatherers to fix communities in the land had been a big driver for predicting the season etc through stone/wood circles. As the OZ aborigines seem to have stayed with hunter gatherer for a lot longer it would be interesting to know what the drivers would have been in this type of community?
I'd guess that predicting seasons had great value with respect to wet seasons/dry seasons and migration of animals, etc so would be useful to H/Gs as well - as you can see I come from the "utility" wing of the party as opposed to the "ritual" wing :-)