As of now with respect to voting, depends on the State.
The SCOTUS is supposedly going to weigh in soon.
If it is a State call (as per the Constitution), then the COMMUNIST STATES will of course allow felons to vote.
The FREE states can decide for themselves.
If FEDGOV decides it has the power, then all bets are off.
The question here isn't what's currently legal/illegal, but about what ought to be: the philosophy underlying jurisprudence.
I notice you don't answer the question: does the serving of a sentence pay one's debt to society or not?
This is a general question, not a specific one — Reiterating: If a sentence does not pay one's debt to society
, then what is its purpose?