Liana Chases Aksai
The 2nd-order formations couldn't be executed by random Spirit cultivators.
The cultivators involved needed to be thoroughly trained before they could even think about using the battle formation on a real battlefield.
There were other complexities involved in 2nd-order battle formations that made them unsuitable for many Spirit cultivators. This was why even the Big Five sects and some influential cultivation families only offered 1st-order battle formations to their members.
It was very uncommon for Foundation Building Experts to execute a battle formation against their enemies. It was said that the Foundation Building Experts who studied the 2nd-order battle formations did not have much individuality of their own. Most of them had to abandon the cultivation technique that was suitable for them and had to adopt a group-based cultivation technique compatible with the battle formation itself.