Busbar or terminal for subpanel?

[Clairebear]

I bought this duel bus bar for a small, 5 switch sub panel I installed. Top connection is from battery and others are from subpanel. On the panel is a 6amp freshwater pump, and two usb ports for phone and ipad. When I see sub panel installation videos and they always use terminals and not busbars, is there any safety reasons why I can’t use this? Just making sure this busbar is capable of handling my loads, everything works just fine and may only add one more thing to the switch down the road but making sure everything safe.

[bil56]

The upper battery connection has the same section as the other 4 sub-panel connections, what will happens if all 4 consumers operate at the same time ?...