That is not the case. The gas pipeline allows for connections to...

That is not the case. The gas pipeline allows for connections to it, but spurs are generally funded by the miner, unless a third party or the pipeline owner see an advantage for themselves to do it. Given the extension will likely be regulated by the Economic Regulation Authority of WA, meaning access tariffs are capped, I doubt the pipeline owner would build/finance the spur itself and have the risks associated with building for a single supply source miner. So pipeline funding to TMT, for example, will be by the miner IMO.

In terms of why, suspect the main benefit to AVL is reduced finance cost in a period where finance is difficult for explorers wanting to be miners. It is a capex funding considerations as against opex cost consideration IMO here as to why mainly.
All IMO