When would I use a 4-20mA differential current input?
For both voltage and current I/O, single-ended circuit have one of their wires connected to a known potential (GND or power), while in the differential circuits both wires may be at arbitrary potentials. Thus, any transmitter with 2 wire interface may operate in either mode (with the exception of externally powered/grounded device with non-isolated outputs)

Differential inputs has higher common-mode noise immunity, higher immunity to noise on power lines, and lower voltage on wire (the datasheet claims &lt;10V common mode for differential, while single-ended will have one wire at 24 volt)

Single ended inputs are easier to make, so they are likely cheaper; you can also simplify wiring by sharing a single common wire between multiple sensors (but this will make sensors more noise sensitive). On the other hand, if the wire detaches from sensor and contacts ground (say because you did not tighten the screws properly), you short your 24V psu to ground, which is a bad thing.