One issue I've ran into is that when you die, your last save file is loaded instead of just respawning at the beginning of the area. Is that just me?
That is intended; The Auto save feature should have it so that when you enter a new area, so that when you are defeated, it should spawn you back to the very start. The game will automatically load whatever the newest save file is, so keep that in mind!
Okay, but elsewhere in the game it says that you lose half your gold when you respawn. So what's the purpose of the bank other than to keep goblins from stealing your gold?
That is mainly a multiplayer feature; In Coop if you are defeated, you lose half your gold but can still resurrect party members by exiting the map. The Bank also makes it easier to send gold to other players so they can purchase items in multiplayer!
In Addition to this, the Hawkman has some benefits to when he uses the bank in both Singleplayer and Multiplayer!