Full democracy is a legitimate demand but one that you need to be extremely optimistic, to say the least, to believe that the central government will agree to budge on.
On the other hand, demands regarding rioting are unreasonable. There objectively has been rioting going on and no government will accept to send the message that it is acceptable to throw petrol bombs or to ransack government buildings, or to use violence in general. The only leeway in these cases is usually the penalty courts hand: Very heavy to send a message or relatively light to appease.
If the economy suffers too much, there will be real internal pressure against protesters, especially against any violence.
If the bill is indeed withdrawn it allows protesters to stop while claiming a victory. This does not mean giving up on broader democratic demands but allows them to catch their breath and ponder a long term strategy.