Jesus did not perform miracles to just demonstrate power. The miracles were also a preaching of the gospel.
When he cured someone of a disease, he was also proclaiming their souls were broken, just like there bodies were. And as he had the power to mend their bodies, he had the power to mend their souls.
When they were surrounded by a hungry crowd, and it was impossible to feed them, he fed them, they were satisfied, and they had enough leftovers that a sizable part of the crowd could have had lunch the next day. There is an ability to feed the hunger of the soul in Jesus. And not of a few, who had to struggle through hours, days and weeks of prayer, fasting and meditation. Soul satisfaction can come by sitting and waiting for Jesus to serve you.
Human beings live on multiple kinds of fuel. Some fuels – eg. love and mission – require taking action. Some fuels – eg. receiving love and forgiveness – require open hands and acceptance.