There is a limit to how much life energy plants will be willing to give away for free before they start to experience adverse effects.
Even with the Plant Affinity and Communication talent, no plant will give them life energy at the cost of their lives. So those who want life energy to cultivate with will have to pay for the life energy with something that the plants want.
To top things off, he has to always go looking for plants to gain life energy from them. Compared to the benefits that he gains from the Fate Binding divine ability, which enables him to cultivate faster no matter where he is, using the wood vessel seems lackluster.
He was thinking about this when he received a message from Stella asking about the storm over his island. She was asking to know if something had gone wrong with his cultivation.
