I think there is confusion.
A thermostat display can be analogue or digital
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but an analogue thermostat can send digital ( on / off ) commands to the boiler.
Not really
To my mind the important bit is how it talks to the boiler, the thermostat to left can only tell the boiler off/on, the thermostat to right has the option to be connected off/on or using OpenTherm when it tells boiler to turn up or down, connection to boiler ebus with for example OpenTherm is analogue control, it is also duel digital and analogue display round the edge showing both set point and current temperature is analogue, and in the centre digital and the centre display can be selected so you can have it show the date if required.
As one would expect the one to left around £35 and one to right around £190. When controlling a modern gas boiler with digital the main idea it to stop the boiler cycling, it does not control room temperature, it simply switches it off when weather warms up, with both thermostats they can be programmed, to the left it doubles as a frost stat, so instead of turning boiler completely off, it will allow it to fire up over night if it gets too cold, but on heating it can easy over shoot and it relies on the TRV to do their job, the one to right has built in algorithms so it works out the over shoot and compensates.
Since I use oil there is little advantage between the two, as my boiler is simply on or off, but with modulating gas boilers there is a huge advantage using the ebus control. The cooler the return water the more efficient the boiler runs, gaining the latent heat from flue gases, also as long as room is to temperature the cooler the radiator the quicker it can turn off when for example sun shines through bay windows and heats the room, and with ebus control hysteresis is eliminated.
However the Nest Gen 3 shown I would not rate as a good wall thermostat because it does not interact with the TRV heads, maybe the new Gen 4 does, I have not looked at the specs.