I have all my body parts intact and operating. But suppose my tongue decided to hitchhike across country, independent of me. I would be lacking an important part, and the tongue would be dying while making great speeches to itching ears that also were hitchhiking away from their former bodies. There' no ministry in that.
The precedent set in scriptures is for every believer to be accountable to fellow worshipers. It doesn't have to be a particular denomination, but must be with other disciples of Christ. Without regular fellowship, independence slowly becomes a curse. A hummingbird showed up here in the cold, very thin, entirely alone. He had better join the others soon.
A pastor sitting at his fireplace heard a knock at the door. He invited in a man of his congregation. "Have a seat, warm yourself."
The man began to warm, then announced "Pastor, I don't think I require assembling as often as the church wants to, as I can make it fine on my own now."
The pastor sat silent, both watching the fire. The pastor reached for the poke, found a nice glowing coal, then moved it from the fire onto the hearth by itself. The coal dimmed, then was black, while the other piled coals glowed happily.
"Pastor, I understand, I'll be there Sunday."