Questions about activation fee/unlocked phone from Apple
I bought an unlocked iPhone 12 at an Apple store today and was charged around a $30 activation fee. I'd already contacted my carrier beforehand to send me a replacement sim for my new phone, which will have the same number and cellular plan of my old phone.
1) Since I paid the activation fee, am I still able to use the (physical) replacement sim card when it arrives?
2) Is my phone truly unlocked and able to connect to any carrier in the future even though I paid for the activation fee?
3) What exactly is the activation fee for? I literally just bought the device and didn't get any additional services performed, i.e. no trade-in, no data transferred, and no sim card transferred. The only information I gave the Apple employee was the name of my carrier.