Unlike jury service, you can refuse point blank to vote. You cannot be a juror if you are over the age of 75. All sorts of people are exempt from jury service.
And anyone else with a job could probably get out of it if they badgered the doctor enough; the argument is a valid one that most working people's mental health would be adversely affected by the consequences of having to take an indefinite amount of time off.
Leaving only people who, although of working age and at least officially in reasonable to good health, either have nowhere else to be for an open-ended length of time, or have thrown everything else to the wind for the once in a lifetime opportunity to fulfil a lifelong yearning to hang, draw and quarter someone.
Juries are a good idea in principle.