They don't get benefits while they're in prison anyway!
I think, instead of prison, they should help to fund the rebuilding and cleaning of what they were proven to be involved in, and they should help the builders physically in the building. They should also be made to apologise to each shop-keeper, each employee and each family they disturbed. Put their wrongs right, so to speak. The guys who injured or killed people should be in prison automatically.
ETA: Like, I mean, what people were found guilty of being involved in, the cost should be split between those charged & then they could have like, a payment plan so they'd be paying for most of their lives. It shows them the sheer consequence and humility of what they did, and the Government wouldn't be out of pocket since they'd be paid back.