- Uses the same antenna.
- Currently most software does'tdoesn't allow to be in client and AP mode at the same time.
- Wireless is a half-duplex protocol, except for some really new bleeding edge stuff. The radio can only transmit or receive at one time, it cannot do both at the same time.
Going with point 3, if any software was developed to allow both client and AP mode simultaneously the radio would first need to communicate like a client and then pass the data along as an AP. The latency would be undesirable, and the most likely cause that no one has made software to run both client and AP mode at the same time.