Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to Gunner Conscript may become lethal if an Aura or Equipment attached to it leaves the battlefield or becomes unattached from Gunner Conscript during that turn
However some powerful cards, such as #217: "B
Its naturally weaker in 1v1 formats, as boards usually wont have 13 creatures on them, so cards like Damnation become better options
The additional beginning phase all happens during the current turn
Even better, as a free sacrifice outlet, you can get rid of your creatures at instant speed, triggering any effects you might have in play at any time
This recovers over time or can be exchanged for Pok Gold, meaning real world money