SPI is normally used for inter-connection between two devices on the same board, the cable lengths for an SPI communication should not be very long as it can pick up noise, also the signaling is normally at 5 V DC, so wires must not be long.
LAN is good when distances are large and when several devices have to be inter-connected.
Ideally the sensor must be connected to a control unit that receives the signals from the sensor and the control unit sends the received signals to a PC or another unit via Ethernet.