A better outcome for them. I don't think so... They might just get shot. Push come to shove they are going to end up on the front line. I don't want someone to have my back who doesn't want to be there. Its not about discipline, its about trust... Conscripts can really harm what we call esprit de corps.
Conscripts just aren't good soldiers. History has seen many a war lost because of use of conscripts.
I think there's better things to do than prisons for sure... There is public service that can be done. I think a military-like public service could be one example of such a thing. Perhaps instead though its about cleaning up/maintaining parks or something like that instead of national defense, where the results aren't so dire...