Well, I would say analog only transmitters are easier to maintain in many ways. So, to calibrate there’s usually only a span and Zero trim pot. This is how you calibrate it, with a trim pot. Some may have a dampen pot to create some smoothing in the output signal. Both smart and analog sensors (like pressure transmitters) need to be serviced in a same way if they get fouled around the diaphragm. I like analog only sensors, I think their simplicity can add to reliability for some instances. For example, some smart transmitters cannot handle heat as well and may have some reading errors due to environmental factors. But Smart Transmitters can be simple to set up to once you get familiar to the menu structure or your communicator. Also, smart transmitters may be used in a wider range of applications maybe repurposing transmitter where where some analog transmitters can have narrower range of working temp or pressure .
Also, many smart transmitters are using Bluetooth and password protect. This can help access transmitters even if your communicator is not working, broken or far away. Also, there are advanced diagnostics in many smart transmitters and you can take snapshots of things like ambient temp, electronics temp, ambient pressure, supply voltage, signal output and strength of signal. All these parameters can help in diagnosing issues and sometimes with less tools and time.