ATP/CTP Based on Planning Data- Clarifications

All below are ATP/CTP Based on Planning Data:

1)Implications of enabling ATP(Enable ATP check box) in while running plan and not enabling ATP check box.?

2)I am running a Plan with ATP enabled, what benefits we get if i run with 24x7 ATP and what benefits we get if without 24x7 ATP. Basically would like to know the functionality of 24x7 ATP.

3)Have set up plan without ATP,
After plan run if i create new sales order will it be shown in planning workbench?
If it is not showing up what could be the reason.
When this new sales order is expected to be shown as Majenta color in planning workbench.