Is the planning module in our new ERP enough?

It depends on how much uncertainty your Supply Chain carries. ERP planning modules are built on deterministic MRP logic: one forecast number, fixed lead times, static safety stock. That works when demand is stable and suppliers are reliable. When demand is volatile or lead times move, the module produces a plan that planners then correct by hand, which is why so many teams who own one still plan in spreadsheets beside it. A probabilistic approach models the distribution of demand and of lead times, and sizes buffers from that uncertainty, updating them as it changes. It is a different calculation, not a better-configured version of the same one.