@Nero
Transferring Qi from the cultivator to the artifact has its own conversion efficiency. Likewise using Qi to directly block attacks has a different conversion efficiency.
Qi Barrier bonuses are far far more common than Artifact Conversion bonuses, however, making artifacts with high max Qi poor at defense. They will commonly lose ALL of their Qi to each attack, draining tons of Qi off your character at low efficiency.

Unless you practice a Law with Qi->Artifact conversion bonuses like Seven Slaughter Sword then your Qi Barrier is almost always more efficient than your artifact.

For example when facing a tribulation you might block 10000 damage with your artifact and spend 5000 Qi, or you could just tank it without an artifact and block 20000 damage with your Qi Barrier directly.

Pls can you elaborate why you think that max qi is detrimental to artifacts ?