He's trying to bash against his cage. Egoist like Trump do not like to be under anyone or be told to do anything.
I wish I could say it is like 4d chess or something, but no. There is nothing good that will come from him in prison.
He won't be able to talk to anyone. Speak to anyone. Travel. Golf. Fly in expensive jets. Share classified documents. Sex. Everything he does from breathing to pissing will be monitored 24/7.
Worse, it gets the US government in the habit of imprisoning someone like Mr. Trump.
Maybe he'll get a martyr complex, but even then, all that does is put him in an disadvantageous position to get his branding of message across, or to spin the narrative. He'd have to rely on his followers.... which is starting to become more slim fan-club by the day.