The main reason why we ''Disposition'' a call, is because when we finish it, we need to submit an internal reason why this customer hung up so, in this way we can justify if it's neccessary to call the customer back at any point bringing him/her back into our list or mark as a sale that was made or into the ''Do not call'' list if requested by them.
After we tap on one of the options, depending on what happen on the call, the dialer will take us back at the ''Available'' status, and we'll keep getting more calls.