> As far as I know, the only reason spoofing is even possible, is so that call centers in other countries can pretend to be calling from a local number, which.. why is that even a feature?

It is very common for each individual phone in a call center to have a direct inward dial number, but when they dial out they want the main support contact number to be displayed so you can get routed appropriately and not harass their tech support employee.