I'm pretty certain that Pieter Doensen is wrong.

The original Roamer microquartz might, in '72, arguably have been the first slightly affordable quartz watch, but I've got one somewhere and it's got a really weird kind of stepper escapement which has a stupidly loud tick. Solid state it ain't.
There's also a Roamer microquartz digital which is nice and early but this solid state version used a dynamic scattering (DMS) LCD with its own bespoke micro-transformer to get a high enough voltage to get the scattering effect in the substrate. In '72, DMS tech was absolutely cutting edge and more expensive than the quartz it was displaying. Any watches using this tech were huge and not remotely cheap.
Eventually Roamer produced a cheaper model with what has become the standard Twisted Nematic (TN) display. but that was too late to be the first of anything.

That there are three very different watches with basically the same name makes it an easy mistake to make. However, one wasn't solid state, one wasn't early and one wasn't cheap.