How easy to redeem points for sleeper accommodations?
 

I am trying to decide whether to get a Guest Rewards credit card to try to rack up points. Does anyone know how easy it is to use Guest Rewards points for sleeper accommodations (with regard to availability, etc)? I could not really get a straight answer from the Amtrak CSR on the phone. If I accumulate tens of thousands of points in my GR account, will I be able to use them, or will I find that they are not really useable because too few sleeper reservations are allocated for Guest Reward redemptions? (Finally, am I crazy to consider this at all, given Amtrak's constant threats to discontinue service?)